Physics Center

Scientists Develop World's Fastest Graphene Transistor

2009-01-06T01:38:00.000-08:00

IBM Scientists from the company&acutes T. J. Waston Research Center have demonstrated the operation of a graphene field-effect transistors at GHz frequencies. Graphene is a special form of graphite, consisting of a single layer of carbon atoms packed in honeycomb lattice, similar to an atomic scale chicken wire. With a top gate deisgn and a gate length 150 nm, the team has achieved a cut-off frequency of 26 GHz for graphene transistors; the highest frequencies reported so far using this novel non-silicon electronic material.

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First superconducting transistor promises PC revolution

2009-01-06T01:25:00.000-08:00

THE world's first superconducting transistor, a long-standing goal for applied physicists, could lead to dramatically faster microchips.

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The Discovery of the Transistor

2009-01-06T01:06:00.000-08:00

The transistor was invented at Bell Laboratories in December 1947 (not in 1948 as is often stated) by John Bardeen and Walter Brattain. 'Discovered' would be a better word, for although they were seeking a solid-state equivalent to the vacuum tube, it was found accidentally during the investigation of the surface states around a diode point-contact. The first transistors were therefore of the point-contact type. William Shockley, the theorist who was leading the research, knew at once that this was not what he was seeking: at the time he was trying to create a solid-state device similar to what we now call a junction field-effect transistor (JFET).

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Listening To Dark Matter

2008-10-17T11:21:00.002-07:00

A team of researchers in Canada have made a bold stride in the struggle to detect dark matter. The PICASSO collaboration has documented the discovery of a significant difference between the acoustic signals induced by neutrons and alpha particles in a detector based on superheated liquids.

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Dark matter comes out of the cold

2008-10-17T11:21:00.001-07:00

Astronomers have for the first time put some real numbers on the physical characteristics of dark matter.

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Dark Matter

2008-10-17T11:20:00.000-07:00

Nearly 50 years ago, Fritz Zwicky realized that clusters of galaxies consisted predominantly of matter in some nonluminous form. The search for dark matter has dominated cosmology for half a century. Precise measurements were obtained over 20 years ago, when dark matter was first mapped in galaxy halos. Only recently has the existence of dark matter over much larger scales than even galaxy clusters been confirmed.

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The search for dark matter

2008-10-17T11:19:00.002-07:00

Experiments housed deep underground are searching for new particles that could simultaneously solve one of the biggest mysteries in astrophysics and reveal what lies beyond the Standard Model of particle physics.

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What is the Universe Made Of?

2008-10-17T11:19:00.001-07:00

One of the key questions that needs to be answered by astrophysisits is what is really out there? And of what is it all made? Without this understanding it is impossible to come to any firm conclusions about how the universe evolved.

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Dark Matter: Hidden Mass Confounds Science, Inspires Revolutionary Theories

2008-10-17T11:18:00.000-07:00

Once upon a time a bit more than 100 years ago many scientists believed that seemingly empty space wasnt empty at all, but was filled with a substance called luminous ether. This mysterious stuff, never seen in any laboratory on Earth, was thought to explain how gravity from one celestial body could affect another.

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What is Dark Matter?

2008-10-17T11:17:00.000-07:00

We believe that that the Universe is critically balanced between being open and closed. We derive this fact from the observation of the large scale structure of the Universe. It requires a certain amount of matter to accomplish this result. Call it M.

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Cosmic collision reveals dark matter

2008-10-17T11:16:00.000-07:00

New observations of a great big cosmic collision provide the best evidence yet that invisible and mysterious dark matter really does exist.

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Dark matter detected in cosmic crash

2008-10-17T11:15:00.000-07:00

Astronomers say fresh imagery of a powerful collision of galaxy clusters supports the idea that dark matter is something totally separate from ordinary matter.

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Superconductor breakthroughs abound: some like it hot

2008-10-14T03:07:00.000-07:00

Normally, big discoveries in a given field come at the rate of a few a year, if that. However, the past six weeks have seen not one, but a series of announcements that may change the face of superconductivity research. Starting with a publication in the February 23rd edition of the Journal of the American Chemical Society and ending with three separate announcements from various Chinese research groups, these last few weeks have given us the description of a previously unknown class of high temperature superconductors.

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EE Times corrects story on silane as a potential superconductor

2008-10-14T03:05:00.000-07:00

A Canadian-German research team has reported what they say is the first evidence that superconductivity can occur in a common gaseous hydrogen compound -- silane -- when compressed to a solid at very high pressure.

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Scientists Create Zero-Resistance Superconductor

2008-10-14T03:02:00.002-07:00

According to reports, Japanese scientist Yoichi Kamihara has discovered a zero resistance superconductor. Layered in iron and stabilized with phosphorous, the superconductor has a negative resistance at 269º Celsius. Currently he is researching ways to replace the phosphorous with other elements including arsenic.

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Powerful superconductor is in a class all its own

2008-10-14T03:02:00.001-07:00

Superconductivity has perplexed, astounded and inspired scientists ever since it was discovered in 1911. Now, in the latest of a century of surprises, researchers at the National High Magnetic Field Laboratory at Florida State University have discovered unusual properties in a novel superconducting material that point to an entirely new kind of superconductor.

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High-temperature superconductor 'pseudogap' imaged

2008-10-14T03:00:00.000-07:00

Cornell researchers and colleagues have produced the first atomic-scale description of what electrons are doing in the mysterious "pseudogap" in high-temperature superconductors.

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Magnet Controls a Superconductor

2008-10-14T02:58:00.000-07:00

Magnetic fields can destroy superconductivity--the flow of electric current without resistance--so magnets don't usually get along very well with superconductors. But in the April Physical Review B, researchers show that by putting a thin magnetic layer on top of a superconducting film and applying a magnetic field, they can tweak the superconductor’s properties in a useful way. Their arrangement makes the superconductor anisotropic, meaning that more current can flow in one direction than in the perpendicular direction. And the specific orientation of these directions is controllable with another field. The technique has potential for superconducting devices.

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Superconductor electric vehicle

2008-10-14T02:57:00.000-07:00

Sumitomo Electric has developed what is being called the world’s first automobile powered by a superconducting motor. The electric passenger sedan (a modified Toyota Crown Comfort), which is powered by a high-temperature superconducting motor cooled by liquid nitrogen, was unveiled in Osaka on June 12 and will go on display at the Hokkaido Toyako G8 Summit on June 19.

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Superconductors Enter Commercial Utility Service

2008-10-14T02:55:00.000-07:00

2 July 2008—Last Wednesday, American Superconductor officially commissioned the world's first high-temperature superconductor power-transmission cable system to be used in a commercial power grid. Superconductors can supply lots of energy quickly, efficiently, and unobtrusively. They conduct 150 times the electricity of similarly sized copper wires. However, because of technological difficulties, the commercial development of superconductor power-cable systems has been slow.

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Silicon becomes a superconductor

2008-10-14T02:51:00.000-07:00

Silicon -- the archetypal semiconductor -- has at long last been shown to demonstrate superconductivity. By substituting 9% of the silicon atoms with boron atoms, physicists in France have found that the resistance of the material drops sharply when cooled below 0.35 K

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Preparation, Structure and Properties of A High-Temperature Superconductor

2008-10-14T02:50:00.000-07:00

Onnes, a Dutch physicist, discovered in 1911 that mercury loses all resistance to electrical flow when cooled to about 4 K; thus, a current once started will flow continuously. Such a phenomenon is known as superconductivity. At ordinary temperatures, metals have some resistance to the flow of electrons, due to the vibration of the atoms which scatter the electrons. As the temperature is lowered, the atoms vibrate less and the resistance declines smoothly, until the material’s critical temperature, Tc, is reached. At this point, the resistance drops abruptly to zero (figure 1). If an electrical current is started in a superconducting ring, it will continue forever.

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The first Canadian high-Tc superconductor Brock Logo

2008-10-14T02:48:00.000-07:00

Brock University Professors F.P. Koffyberg, F.S. Razavi, and B. Mitrovic of the Physics Department, Division of Maths and Sciences, have proven the existence of a new superconductor.

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Iron Exposed as High-Temperature Superconductor

2008-10-14T02:47:00.002-07:00

For more than 20 years, the only known superconductors that worked far above liquid-helium temperatures were a few dozen compounds—virtually all based on copper. Now scientists have discovered the first high-temperature superconductors based on iron. These novel materials could help unravel one of the biggest mysteries in science—how exactly the high-temperature versions work.

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New Family Of Superconductors Discovered

2008-10-14T02:47:00.001-07:00

University of Saskatchewan Canada Research Chair John Tse and colleagues in Germany have identified a new family of superconductors – research that could eventually lead to the design of better superconducting materials for a wide variety of industrial uses.

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Ceramic Superconductor Single Crystal

2008-10-14T02:43:00.000-07:00

Superconductivity is a phenomenon characterized by the disappearance of electrical resistance in various metals, alloys, and compounds when they are cooled below a certain level, usually termed the critical temperature (Tc). The phenomenon was first observed in 1911 by Heike Kamerlingh Onnes, who noted that the resistance of a frozen mercury rod abruptly dropped to zero when cooled to the boiling point of helium (4.2 Kelvin). Onnes is also credited with realizing that a material in a superconducting state can be returned to its standard, nonsuperconducting condition through exposure to a strong magnetic field of a certain critical value or by passing a large current through it. For his significant findings, Onnes was awarded the 1913 Nobel Prize for Physics. Yet, another 20 years would pass before any other major discoveries regarding superconductors would be unearthed, scientists believing for many years that other than their intriguing lack of resistance, superconductors acted as other materials. In 1933, however, Walter Meissner and Robert Ochsenfeld discovered that superconducting materials displayed an unusually high level of diamagnetism (the ability to repel magnetic fields completely). Now known as the Meissner effect, this property of superconductors is often demonstrated experimentally by the levitation of a magnet over a superconducting material.

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Solar Cell Technologies

2008-10-13T10:08:00.001-07:00

Three key elements in a solar cell form the basis of their manufacturing technology. The first is the semiconductor, which absorbs light and converts it into electron-hole pairs. The second is the semiconductor junction, which separates the photo-generated carriers (electrons and holes), and the third is the contacts on the front and back of the cell that allow the current to flow to the external circuit. The two main categories of technology are defined by the choice of the semiconductor: either crystalline silicon in a wafer form or thin films of other materials.

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An unexpected discovery could yield a full spectrum solar cell

2008-10-13T10:07:00.000-07:00

Researchers in the Materials Sciences Division (MSD) of Lawrence Berkeley National Laboratory, working with crystal-growing teams at Cornell University and Japan's Ritsumeikan University, have learned that the band gap of the semiconductor indium nitride is not 2 electron volts (2 eV) as previously thought, but instead is a much lower 0.7 eV.

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Spray-On Solar-Power Cells Are True Breakthrough

2008-10-13T10:06:00.002-07:00

Scientists have invented a plastic solar cell that can turn the sun's power into electrical energy, even on a cloudy day.

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New World Record Achieved in Solar Cell Technology

2008-10-13T10:06:00.001-07:00

U.S. Department of Energy (DOE) Assistant Secretary for Energy Efficiency and Renewable Energy Alexander Karsner today announced that with DOE funding, a concentrator solar cell produced by Boeing-Spectrolab has recently achieved a world-record conversion efficiency of 40.7 percent, establishing a new milestone in sunlight-to-electricity performance. This breakthrough may lead to systems with an installation cost of only $3 per watt, producing electricity at a cost of 8-10 cents per kilowatt/hour, making solar electricity a more cost-competitive and integral part of our nation’s energy mix.

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Solar Cell Sets World Efficiency Record At 40.8 Percent

2008-10-13T10:05:00.000-07:00

Scientists at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) have set a world record in solar cell efficiency with a photovoltaic device that converts 40.8 percent of the light that hits it into electricity. This is the highest confirmed efficiency of any photovoltaic device to date.

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12-year-old Revolutionizes the Solar Cell

2008-10-13T10:04:00.000-07:00

William Yuan, a seventh-grader from Portland, OR, developed a three-dimensional solar cell that absorbs UV as well as visible light. The combination of the two might greatly improve cell efficiency. William's project earned him a $25,000 scholarship and a trip to the Library of Congress to accept the award, which is usually given out for research at the graduate level.

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How to Build Your Own Solar Cell

2008-10-13T10:03:00.000-07:00

"Cycles of energy and materials have existed on the Earth for billions of years. In a few hundred years, we have come to dominate and control many of these cycles. Our search for artificial photosynthesis is, therefore, not merely to present ourselves with alternatives for powering our society, but it is a search for our place in the Earth's biosphere."

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How Solar Cells Work

2008-10-13T10:02:00.000-07:00

You've probably seen calculators that have solar cells -- calculators that never need batteries, and in some cases don't even have an off button. As long as you have enough light, they seem to work forever. You may have seen larger solar panels -- on emergency road signs or call boxes, on buoys, even in parking lots to power lights. Although these larger panels aren't as common as solar powered calculators, they're out there, and not that hard to spot if you know where to look. There are solar cell arrays on satellites, where they are used to power the electrical systems.

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Quantum Criticality of Heavy Fermions

2008-10-12T02:54:00.000-07:00

Classical phase transitions like the boiling of water are driven by changes of the temperature. At absolute zero temperature, however, so-called quantum phase transitions (QPTs) between competing, nearly degenerate phases may occur. Consequently, such transitions have to be driven by non-thermal control parameters, e.g., pressure, chemical doping and magnetic field. For quite some time, QPTs have been considered mere curiosities in the mind of theoretical physicists, but in recent years they developed into a subject of worldwide research activities of both theorists and experimentalists.

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Fermions Do Avoid Each Other

2008-10-12T02:53:00.000-07:00

Identical fermions are never found close together. For the first time, this assumption has been experimentally demonstrated. For many years, quantum physicists had known theoretically that these elementary particles were incapable of travelling in close proximity. In a beam of such particles, the distance between any pair was supposed to be always greater than a given value, called the “correlation length.”

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Fermions A Member of the Particle Zoo

2008-10-12T02:43:00.000-07:00

The fermions are a class of elementary particles that are defined by their 1/2 integer spin, and the fact that they make up the matter that we interact with everyday.

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Composite fermions and bosons: An invitation to electron masquerade in Quantum Hall

2008-10-12T02:41:00.000-07:00

The two-dimensional electron gas formed at the semiconductor heterointerface is a theater for many intriguing plays of physics. The fractional quantum Hall effect (FQHE), which occurs in strong magnetic fields and low temperatures, is the most fascinating of them. The concept of composite fermions and bosons not only is beautiful by itself but also has proved highly successful in providing pictorial interpretation of the phenomena associated with the FQHE.

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First Direct Evidence of Dirac Fermions in Graphite

2008-10-12T02:39:00.000-07:00

The recent surge of interest in the electronic properties of graphene—that is, isolated layers of graphite just one atomic layer thick—has largely been driven by the discovery that electron mobility in graphene is ten times higher than in commercial-grade silicon, raising the possibility of high-efficiency, low-power, carbon-based electronics. Scientists attribute graphene's surprising current capacity (as well as a number of even stranger phenomena) to the presence of charge carriers that behave as if they are massless, "relativistic" quasiparticles called Dirac fermions. Harnessing these quasiparticles in real-world carbon-based devices, however, requires a deeper knowledge of their behavior under less-than-ideal circumstances, such as around defects, at edges, or in three dimensions—in other words, in graphite. At the ALS, a team of researchers using angle-resolved photoemission spectroscopy (ARPES) have now produced the first direct evidence of massless Dirac fermions in graphite coexisting with quasiparticles of finite effective mass and defect-induced localized states.

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When bosons behave like fermions

2008-10-12T02:37:00.000-07:00

Physicists have blurred the distinction between bosons and fermions by coaxing a one-dimensional gas of atoms into a Tonks-Girardeau gas for the first time. The creation of this novel quantum state, which was first predicted about 40 years ago, represents yet another breakthrough in the field of ultracold physics (B Paredes et al. 2004 Nature 429 277).

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Code for ‘Unbreakable’ Quantum Encryption Generated at Record Speed over Fiber

2008-10-10T09:48:00.000-07:00

Raw code for “unbreakable” encryption, based on the principles of quantum physics, has been generated at record speed over optical fiber at the Commerce Department’s National Institute of Standards and Technology (NIST). The work, reported today at the SPIE Defense & Security Symposium in Orlando, Fla.,* is a step toward using conventional high-speed networks such as broadband Internet and local-area networks to transmit ultra-secure video for applications such as surveillance.

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Quantum Encryption as a Step Closer to Total Secrecy

2008-10-10T09:47:00.000-07:00

The first computer network in the world protected by an “unbreakable” security system based on quantum encryption has been unveiled at a Viennese scientific conference.

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Team Sends Quantum Encryption 'Keys' Over Record Distances

2008-10-10T09:46:00.000-07:00

Using an innovative sensor for detecting single photons, the smallest particles of light, scientists from Los Alamos National Laboratory (LANL), the National Institute of Standards and Technology (NIST) and Albion College (Albion, Mich.) have set two significant distance records for distributing "keys" (or codes) for quantum encryption, the most secure method known for protecting the privacy of information.

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Quantum attacks worry computer scientists

2008-10-10T09:44:00.000-07:00

In the weird world of quantum computing, the state of computer systems networked together is so fragile that a read access to a single quantum bit, or qubit, on one machine would require a network-wide reset. It's no wonder, then, that two researchers who are working on ways of defending against the future possibility of malicious attack assume that any unauthorized access to a quantum computer constitutes a catastrophic failure.

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Quantum encryption and the weakness of European science

2008-10-10T09:42:00.000-07:00

This week in Vienna, researchers demonstrated a working quantum key distribution (QKD) network, a feat that produced some good news and some bad news. The good news is that Siemens is probably going to be selling this stuff in a year or so; IT professionals, get ready to open your check books. On the other hand, by doing such a demo, the researchers show that QKD has passed from the realm of science into engineering, and they illustrate the weakness of fundamental scientific research in Europe.

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Quantum Encryption - An Introduction

2008-10-10T09:41:00.000-07:00

“AT THE speed of light, Hephaestus’s sacred fire/ Blazed from beacon tower to beacon tower.” Thus, according to Aeschylus, spake Clytemnestra, an ancient queen of Mycenae, explaining how she received tidings that her husband Agamemnon was on his way home from the Trojan war. Perhaps Agamemnon would have done better to have turned up unannounced. The news left the queen and her lover just enough time to plot the cuckold’s assassination.

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Nuclear Magnetic Resonance Spectroscopy

2008-10-05T19:16:00.000-07:00

Over the past fifty years nuclear magnetic resonance spectroscopy, commonly referred to as nmr, has become the preeminent technique for determining the structure of organic compounds. Of all the spectroscopic methods, it is the only one for which a complete analysis and interpretation of the entire spectrum is normally expected. Although larger amounts of sample are needed than for mass spectroscopy, nmr is non-destructive, and with modern instruments good data may be obtained from samples weighing less than a milligram. To be successful in using nmr as an analytical tool, it is necessary to understand the physical principles on which the methods are based.

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Nuclear Magnetic Resonance Spectroscopy

2008-10-05T19:15:00.000-07:00

Nuclear Magnetic Resonance spectroscopy is a powerful and theoretically complex analytical tool. On this page, we will cover the basic theory behind the technique. It is important to remember that, with NMR, we are performing experiments on the nuclei of atoms, not the electrons. The chemical environment of specific nuclei is deduced from information obtained about the nuclei.

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Drexler and Smalley make the case for and against 'molecular assemblers'

2008-10-05T19:04:00.000-07:00

In this C&EN exclusive "Point-Counterpoint," two of nanotechnology's biggest advocates square off on a fundamental question that will dramatically affect the future development of this field. Are "molecular assemblers"--devices capable of positioning atoms and molecules for precisely defined reactions in almost any environment--physically possible?

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Developing Molecular Manufacturing

2008-10-05T18:59:00.000-07:00

Any of several diverse pathways might be used to develop molecular manufacturing. There are many strategies, techniques, and tools that may contribute to its development. Further study will be needed to decide which approach is best. Questions to be answered for each approach include the effort required to develop it, the performance (throughput and cost) of the manufacturing system, and the performance of the products.

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The new industrial revolution of Nanotechnology

2008-10-05T18:58:00.000-07:00

Nanotechnology is not an individual science or technology. It is a uniting expression for the multi-disciplinary area of production technologies operating in the area of extremely small size particles and materials starting from individual atoms and molecules. Hundreds of products involving nanotechnology are already available and the future applications seem endless in the areas such as biomedicine, computers, consumer products and energy.

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The Ethics and Politics of Nanotechnology

2008-10-05T18:56:00.000-07:00

NANOTECHNOLOGY could become the most influential force to take hold of the technology industry since the rise of the Internet. Nanotechnology could increase the speed of memory chips, remove pollution particles in water and air and find cancer cells quicker. Nanotechnology could prove beyond our control, and spell the end of our very existence as human beings. Nanotechnology could alleviate world hunger, clean the environment, cure cancer, guarantee biblical life spans or concoct super-weapons of untold horror. Nanotechnology could be the new asbestos. Nanotechnology could spur economic development through spin-offs of the research. Nanotechnology could harm the opportunities of the poor in developing countries. Nanotechnology could make the molecules in ice cream more uniform in size. Nanotechnology could enable a digital camera to work in the dark. Nanotechnology could clean up toxic waste on the atomic level. Nanotechnology could change the world from the bottom up. Nanotechnology could become an instrument of terrorism. Nanotechnology could lead to the next industrial revolution. Nanotechnology could transform the food industry. Nanotechnology could repair the ozone layer. Nanotechnology could change everything.

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Our Silver-Coated Future

2008-10-05T18:51:00.000-07:00

Nanotechnology, fast becoming a three-trillion-dollar industry, is about to revolutionize our world. Unfortunately, hardly anyone is stopping to ask whether it's safe.

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How Atomic Clocks Work

2008-09-30T21:21:00.000-07:00

When the power goes out and is later restored, how do you know what time to set your clocks to? Have you ever wondered how time is regulated?

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What's a uranium centrifuge?

2008-09-30T21:20:00.002-07:00

Uranium is an element that is similar to iron. Like iron, you dig uranium ore out of the ground and then process it to extract the pure uranium from the ore. When you finish processing uranium ore, what you have is uranium oxide. Uranium oxide contains two types (or isotopes) of uranium: U-235 and U-238. U-235 is what you need if you want to make a bomb or fuel a nuclear power plant. But the uranium oxide from the mine is about 99 percent U-238. So you need to somehow separate the U-235 from the U-238 and increase the amount of U-235. The process of concentrating the U-235 is called enrichment, and centrifuges are a central part of the process.

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How Radiation Works

2008-09-30T21:20:00.001-07:00

Say the word "radiation" to three different people, and you'll probably get three different reactions. Your aunt may tell you how radiation destroyed her cancer. Your neighbor might mention the "duck and cover" procedures of his day. And your comics-loving friend will explain how gamma rays turned Bruce Banner into The Hulk. Radiation comes in many forms and is all around us, all the time. Sometimes it's dangerous; sometimes it's not.

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How Nuclear Radiation Works

2008-09-30T21:19:00.002-07:00

You've probably heard people talk about radiation both in fiction and in real life. For example, when the Enterprise approaches a star on "Star Trek," a member of the crew might warn about the radiation levels. In Tom Clancy's book "The Hunt for Red October," the Russian submarine has a nuclear reactor accident with radiation leakage that forces the crew to abandon ship. At Three Mile Island and Chernobyl, nuclear power plants released radioactive substances into the atmosphere during nuclear accidents.

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How Nuclear Fusion Reactors Work

2008-09-30T21:19:00.001-07:00

Fusion reactors have been getting a lot of press recently because they offer some major advantages over other power sources. They will use abundant sources of fuel, they will not leak radiation above normal background levels and they will produce less radioactive waste than current fission reactors.

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Can people get poisoned by indirect exposure to polonium-210?

2008-09-30T21:17:00.000-07:00

On Thursday, November 23, former Russian spy Alexander Litvinenko died in a London hospital of radiation poisoning. Doctors determined that he'd been given a lethal dose of the radioactive isotope polonium-210, which they found in his urine before he died. Since then, authorities have found traces of radiation, in most cases openly attributed to polonium-210, in at least 10 places known to have been visited by the victim after he began feeling ill on November 1. The sites include Litvinenko's home, one restaurant, a hotel, the office suite of a security company and the office of one of Litvinenko's friends. In addition, scientists have found traces of radiation in two British Airways jets that had flown routes between London and Moscow in the weeks before Litvinenko's death. Ripples of concern have spread through Britain: Are the tens of thousands of people who were in those buildings or on those planes in the last month at risk of radiation poisoning?

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How Nuclear Power Works

2008-09-30T21:16:00.000-07:00

When you hear the words "nuclear power," different images may flicker through your mind: concrete coolant towers emitting torrents of steam, a mushroom cloud rising high into the sky or even Homer Simpson asleep at the control panel.

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Wormhole

2008-09-30T21:09:00.000-07:00

In physics, a wormhole is a hypothetical topological feature of spacetime that is basically a 'shortcut' through space and time. Spacetime can be viewed as a 2D surface, and when 'folded' over, a wormhole bridge can be formed. A wormhole has at least two mouths which are connected to a single throat or tube. If the wormhole is traversable, matter can 'travel' from one mouth to the other by passing through the throat. While there is no observational evidence for wormholes, spacetimes-containing wormholes are known to be valid solutions in general relativity.

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Journey to A Black Hole

2008-09-30T21:05:00.000-07:00

We must know where to find a black hole before we can travel to it. But how can we find black holes? Although they do not emit any light, they do reveal themselves in other ways.

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What Happens if You Fall Into a Black Hole?

2008-09-30T20:59:00.002-07:00

The world's largest scientific instrument, the Large Hadron Collider, was switched on in Switzerland on Wednesday. A few people worried that the LHC would cause the world to be swallowed up by a black hole, especially when it starts to operate at full force in the spring. What would happen if you fell into a black hole?

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Entropy and the Laws of Thermodynamics

2008-09-30T20:59:00.001-07:00

The principal energy laws that govern every organization are derived from two famous laws of thermodynamics. The second law, known as Carnot's principle, is controlled by the concept of entropy.

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Entropy Explained

2008-09-30T20:57:00.000-07:00

The concept of entropy is generally not well understood among laymen. With the help of several physicists, including Wolfgang Gasser and Malcolm Schreiber, I have composed the following article in an attempt to correct a common misunderstanding.[1] Contrary to what many laymen think, there is no Law of Entropy which states that order must always decrease. That is a layman's fiction, although born from a small kernel of reality. The actual Law of Entropy is better known as the Second Law of Thermodynamics. The First Law is that energy is not created or destroyed, and the Third Law is that absolute zero cannot be achieved--each of these laws is actually entailed from the first, in conjunction with certain other assumptions. But it is the Second Law that many laymen incorrectly think says that order must always decrease.

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Laws of Thermodynamics

2008-09-30T20:56:00.000-07:00

Energy exists in many forms, such as heat, light, chemical energy, and electrical energy. Energy is the ability to bring about change or to do work. Thermodynamics is the study of energy.

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Communicating with Light – Fibre Optics

2008-09-30T20:55:00.000-07:00

Since the earliest times people have wanted to send messages to each other over distances. Once you get too far away to shout or see hand signals you have to use something else. All kinds of things have been tried – banging on hollow trees or drums and even tapping on walls. You know the kind of thing: one bang for 'yes' and two bangs for 'no'. Smoke signals by day and fires by night have used light to transmit information. In places like Egypt where sunshine was reliable, people developed a system of signalling using mirrors to reflect the sun and send 'flashes'. The most advanced version of this device (called a heliograph) had two moving mirrors so that one could pick up sunlight and the other could flash signals in any direction.

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Basic Principles of Fiber Optics

2008-09-30T20:52:00.002-07:00

Since its invention in the early 1970s, the use and demand of optical fiber has grown tremendously. The uses of optical fiber today are quite numerous. The most common are telecommunications, medicine, military, automotive, and industrial.

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Quantum Computer "Running"

2008-09-30T20:52:00.001-07:00

Quantum computer solves problem, without running

2008-09-30T20:44:00.002-07:00

By combining quantum computation and quantum interrogation, scientists at the University of Illinois at Urbana-Champaign have found an exotic way of determining an answer to an algorithm – without ever running the algorithm.

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What is a Quantum Computer?

2008-09-30T20:44:00.001-07:00

Behold your computer. Your computer represents the culmination of years of technological advancements beginning with the early ideas of Charles Babbage (1791-1871) and eventual creation of the first computer by German engineer Konrad Zuse in 1941. Surprisingly however, the high speed modern computer sitting in front of you is fundamentally no different from its gargantuan 30 ton ancestors, which were equipped with some 18000 vacuum tubes and 500 miles of wiring! Although computers have become more compact and considerably faster in performing their task, the task remains the same: to manipulate and interpret an encoding of binary bits into a useful computational result. A bit is a fundamental unit of information, classically represented as a 0 or 1 in your digital computer. Each classical bit is physically realized through a macroscopic physical system, such as the magnetization on a hard disk or the charge on a capacitor. A document, for example, comprised of n-characters stored on the hard drive of a typical computer is accordingly described by a string of 8n zeros and ones. Herein lies a key difference between your classical computer and a quantum computer. Where a classical computer obeys the well understood laws of classical physics, a quantum computer is a device that harnesses physical phenomenon unique to quantum mechanics (especially quantum interference) to realize a fundamentally new mode of information processing.

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Electrophysiology of plant protoplasts in comparison of their intact cells

2008-09-30T20:26:00.000-07:00

Isolation of protoplasts from plant cells suitable for electrophysiological studies.

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Relativity and the Cosmos

2008-09-30T20:24:00.000-07:00

In November of 1919, at the age of 40, Albert Einstein became an overnight celebrity, thanks to a solar eclipse. An experiment had confirmed that light rays from distant stars were deflected by the gravity of the sun in just the amount he had predicted in his theory of gravity, general relativity. General relativity was the first major new theory of gravity since Isaac Newton's more than 250 years earlier.

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Introduction to Differential Geometry and General Relativity

2008-09-30T20:23:00.000-07:00

Here, we do just enough topology so as to be able to talk about smooth manifolds. We begin with n-dimensional Euclidean space.

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General Relativity

2008-09-30T20:18:00.000-07:00

General relativity is a theory of gravitation and to understand the background to the theory we have to look at how theories of gravitation developed. Aristotle's notion of the motion of bodies impeded understanding of gravitation for a long time. He believed that force could only be applied by contact; force at a distance being impossible, and a constant force was required to maintain a body in uniform motion.

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Beyond Big Bang Cosmology

2008-09-30T03:46:00.001-07:00

The Big Bang model is not complete. For example, it does not explain why the universe is so uniform on the very largest scales or, indeed, why it is so non-uniform on smaller scales, i.e., how stars and galaxies came to be.

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Big Bang

2008-09-30T03:43:00.000-07:00

Tests of Big Bang Cosmology

2008-09-30T03:42:00.000-07:00

The Big Bang Model is supported by a number of important observations, each of which are described in more detail on separate pages:

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Big Bang Cosmology Primer

2008-09-30T03:39:00.000-07:00

The steady state theory of cosmology claims that the Universe simply exists without changing with time. This theory presents many physical as well as philosophical difficulties. Evidence suggests that the Universe is expanding. While there are ways to explain expansion in a steady state universe, few astrophysicists believe this theory, because there is little evidence to support it. As the first widely held theory about the Universe it is included here for historical completeness.

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Big Bang Theory - The Premise

2008-09-30T03:34:00.000-07:00

The Big Bang theory is an effort to explain what happened at the very beginning of our universe. Discoveries in astronomy and physics have shown beyond a reasonable doubt that our universe did in fact have a beginning. Prior to that moment there was nothing; during and after that moment there was something: our universe. The big bang theory is an effort to explain what happened during and after that moment.

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Basic Electronics

2008-09-30T03:33:00.000-07:00

Consider the following analogy. The water system in your house probably has a “tank” located somewhere high, maybe in the loft. You have pipes that link it to taps (faucets) somewhere lower, say, in your kitchen. When you open a tap the water flows. In this analogy the force pushing the water out of the tap (gravity) is analogous to voltage and the quantity of water flowing per second represents the electrical current. In the electrical circuit equivalent of this we could imagine a battery providing the voltage and wires linking the + and – terminals via a switch. When the switch is closed current flows through the wires. In this case the current is a flow of electrons, invisible to the naked eye but unmistakably present. One word of warning … in general it is not a good idea to connect a wire directly across the terminals of a battery since this provides a path of very low resistance for the current and will very quickly drain the battery and ,depending on the wire used and the capacity of the battery, may result in overheating.. It is analogous to opening the tap fully or, in fact, removing it completely allowing the water to flow un-restricted out of the tank.

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String Theory

2008-09-30T03:27:00.000-07:00

Quantum Time Waits for no Cosmos

2008-09-30T03:26:00.000-07:00

THE INTRIGUING notion that time might run backwards when the Universe collapses has run into difficulties. Raymond Laflamme, of the Los Alamos National Laboratory in New Mexico, has carried out a new calculation which suggests that the Universe cannot start out uniform, go through a cycle of expansion and collapse, and end up in a uniform state. It could start out disordered, expand, and then collapse back into disorder. But, since the COBE data show that our Universe was born in a smooth and uniform state, this symmetric possibility cannot be applied to the real Universe.

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Introduction to Special Relativity

2008-09-30T03:15:00.000-07:00

Special relativity is a fundamental physics theory about space and time that was developed by Albert Einstein in 1905 as a modification of Newtonian physics. It was created to deal with some pressing theoretical and experimental issues in the physics of the time involving light and electrodynamics. The predictions of special relativity correspond closely to those of Newtonian physics at speeds which are low in comparison to that of light, but diverge rapidly for speeds which are a significant fraction of the speed of light. Special relativity has been experimentally tested on numerous occasions since its inception, and its predictions have been verified by those tests.

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Chaos Theory for Beginners

2008-09-30T03:10:00.000-07:00

Nature is highly complex, and the only prediction you can make is that she is unpredictable. The amazing unpredictability of nature is what Chaos Theory looks at. Why? Because in stead of being boring and translucent, nature is marvelous and mysterious. And Chaos Theory has managed to somewhat capture the
beauty of the unpredictable and display it in the most awesome patterns. Nature, when looked upon with the right kind of eyes, presents herself as one of the most fabulous works of art ever wrought.

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Amazing Astronomy Facts

2008-09-30T03:06:00.000-07:00

When you look at the Andromeda galaxy (which is 2.3 million light years away), the light you are seeing took 2.3 million years to reach you. Thus you are seeing the galaxy as it was 2.3 million years ago.
Light from the sun takes 8 minutes to reach you, thus you see the sun as it was 8 minutes ago. It might have blown up 4 minutes ago and you wouldn't know about it!
The Earth is not a sphere! It actually is an oblate spheroid, it is squashed slightly at the poles and bulges out at the equator due to its rotation.

Quantum Mechanics for Beginners

2008-09-30T03:04:00.000-07:00

Science is exciting because it is always in trouble. No matter how excellent a theory is, it always misses some point or other. Even our most precious ideas about the universe are not able to explain everything; there's always a blind spot. And when the hopeful folks zoom in on that blind spot it pretty much always turns out to be a lot larger than anybody thought, and all of us a mere bunch of naive beginners.

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What is Thermodynamics?

2008-09-30T01:18:00.000-07:00

In physics, thermodynamics (from the Greek θερμη, therme, meaning "heat" and δυναμις, dynamis, meaning "power") is the study of the transformation of energy into different forms and its relation to macroscopic variables such as temperature, pressure, and volume. Its underpinnings, based upon statistical predictions of the collective motion of particles from their microscopic behavior, is the field of statistical thermodynamics, a branch of statistical mechanics. Roughly, heat means "energy in transit" and dynamics relates to "movement"; thus, in essence thermodynamics studies the movement of energy and how energy instills movement. Historically, thermodynamics developed out of need to increase the efficiency of early steam engines.

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What is String Theory?

2008-09-30T01:17:00.000-07:00

String theory is a still-developing mathematical approach to theoretical physics, whose original building blocks are one-dimensional extended objects called strings. Unlike the point particles in quantum field theories like the standard model of particle physics, strings interact in a way that is almost uniquely specified by mathematical self-consistency, forming an apparently valid quantum theory of gravity.

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What is Statistical Mechanics?

2008-09-30T01:16:00.000-07:00

Statistical mechanics is the application of probability theory, which includes mathematical tools for dealing with large populations, to the field of mechanics, which is concerned with the motion of particles or objects when subjected to a force. Statistical mechanics, sometimes called statistical physics, can be viewed as a subfield of physics and chemistry. Pioneers in establishing the field were Ludwig Boltzmann and Josiah Willard Gibbs.

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What is Relativity?

2008-09-30T01:15:00.000-07:00

The theory of relativity , or simply relativity, refers specifically to two theories of Albert Einstein: special relativity and general relativity. However, "relativity" can also refer to Galilean relativity.

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What is Quantum Gravity?

2008-09-30T01:14:00.000-07:00

Quantum gravity is the field of theoretical physics attempting to unify quantum mechanics, which describes three of the fundamental forces of nature (electromagnetism, weak interaction, and strong interaction), with general relativity, the theory of the fourth fundamental force: gravity. One ultimate goal hoped to emerge as a result of this is a unified framework for all fundamental forces— called a "theory of everything" (TOE).

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What is Quantum Field Theory?

2008-09-30T01:13:00.000-07:00

In quantum field theory (QFT) the forces between particles are mediated by other particles. For instance, the electromagnetic force between two electrons is caused by an exchange of photons. But quantum field theory applies to all fundamental forces. Intermediate vector bosons mediate the weak force, gluons mediate the strong force, and gravitons mediate the gravitational force. These force carrying particles are virtual particles and, by definition, cannot be detected while carrying the force, because such detection will imply that the force is not being carried. In QFT photons are not thought of as 'little billiard balls', they are considered to be field quanta - necessarily chunked ripples in a field that 'look like' particles. Fermions, like the electron, can also be described as ripples in a field, where each kind of fermion has its own field. In summary, the classical visualisation of "everything is particles and fields", in quantum field theory, resolves into "everything is particles", which then resolves into "everything is fields". In the end, particles are regarded as excited states of a field (field quanta).

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What is Quantum Optics?

2008-09-30T01:12:00.000-07:00

Quantum optics is a field of research in physics, dealing with the application of quantum mechanics to phenomena involving light and its interactions with matter.

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What is Quantum Mechanics?

2008-09-30T01:11:00.000-07:00

Quantum mechanics is the study of mechanical systems whose dimensions are close to the atomic scale, such as molecules, atoms, electrons, protons and other subatomic particles. Quantum mechanics is a fundamental branch of physics with wide applications. Quantum theory generalizes classical mechanics to provide accurate descriptions for many previously unexplained phenomena such as black body radiation and stable electron orbits. The effects of quantum mechanics become evident at the atomic and subatomic level, and they are typically not observable on macroscopic scales. Superfluidity is one of the known exceptions to this rule.

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What is Quantum Electrodynamics?

2008-09-30T01:10:00.000-07:00

Quantum electrodynamics (QED) is a relativistic quantum field theory of electrodynamics. QED was developed by a number of physicists, beginning in the late 1920s. It basically describes how light and matter interact. More specifically it deals with the interactions between electrons, positrons and photons. QED mathematically describes all phenomena involving electrically charged particles interacting by means of exchange of photons. It has been called "the jewel of physics" for its extremely accurate predictions of quantities like the anomalous magnetic moment of the electron, and the Lamb shift of the energy levels of hydrogen.

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What is Plasma Physics?

2008-09-30T01:09:00.000-07:00

In physics and chemistry, plasma is an ionized gas, in which a certain proportion of electrons are free rather than being bound to an atom or molecule. The ability of the positive and negative charges to move somewhat independently makes the plasma electrically conductive so that it responds strongly to electromagnetic fields. Plasma therefore has properties quite unlike those of solids, liquids or gases and is considered to be a distinct state of matter. Plasma typically takes the form of neutral gas-like clouds (e.g. stars). The explanation of the example, star, is a massive, luminous ball of plasma.

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What is Optics?

2008-09-30T01:07:00.000-07:00

Optics (from ὀπτική, appearance or look in Ancient Greek) is the science that describes the behavior and properties of light and the interaction of light with matter. Optics explains optical phenomena.

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What is Nuclear Physics?

2008-09-30T01:06:00.000-07:00

Nuclear physics is the field of physics that studies the building blocks and interactions of atomic nuclei.

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What is Nanotechnology?

2008-09-30T01:05:00.000-07:00

Nanotechnology or, for short, nanotech, refers to a field of applied science whose theme is the control of matter on an atomic and molecular scale. Generally nanotechnology deals with structures 100 nanometers or smaller, and involves developing materials or devices within that size.

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