Free Republic

A group of physicists at the University of Glasgow is claiming a first: taking photos of entangled photons. In this paper in Nature (hooray for free access!), they explain that their 201 x 201 pixel images captured around 2,500 different entangled quantum states. The entangled photons were imaged using different lens configurations to capture correlations of position and momentum – the characteristics (to shorthand Heisenberg’s uncertainty principle) that mutually preclude excessive knowledge about a given quantum system. From the 100,000 images taken by their setup (pictured*), the scientists say they were able to observe 2,500 states which they described as...

In a paper published in the March 29 issue of the journal Nature, the scientists describe the emergence of “spontaneous coherence,” “spin textures” and “phase singularities” when excitons—the bound pairs of electrons and holes that determine the optical properties of semiconductors and enable them to function as novel optoelectronic devices—are cooled to near absolute zero. This cooling leads to the spontaneous production of a new coherent state of matter which the physicists were finally able to measure in great detail in their basement laboratory at UC San Diego at a temperature of only one-tenth of a degree above absolute zero....

Researchers have bent one of the most basic rules of quantum mechanics, a counterintuitive branch of physics that deals with atomic-scale interactions. Its "complementarity" rule asserts that it is impossible to observe light behaving as both a wave and a particle, though it is strictly both. In an experiment reported in Science, researchers have now done exactly that. They say the feat "pulls back the veil" on quantum reality in a way that was thought to be prohibited by theory. Quantum mechanics has spawned and continues to fuel spirited debates about the nature of what we can see and measure,...

When probing the deepest reaches of the Cosmos or magnifying our understanding of the quantum world, a whole host of mysteries present themselves. This is to be expected when pushing our knowledge of the Universe to the limit. But what if a well-known -- and apparently constant -- characteristic of matter starts behaving mysteriously? This is exactly what has been noticed in recent years; the decay rates of radioactive elements are changing. This is especially mysterious as we are talking about elements with "constant" decay rates -- these values aren't supposed to change. School textbooks teach us this from an...

An artificial "black hole" designed to capture wayward atoms has been created. It paves the way for an atom trap that could yield previously unknown states of matter. A team led by Lene Hau of Harvard University has mimicked the death spiral of matter falling into a cosmic black hole by applying a voltage across a carbon nanotube – a rolled-up sheet of carbon atoms. This created a powerful electric field that tugged at nearby rubidium atoms, which had been chilled to a fraction of a degree above absolute zero: a positive charge on the surface of the nanotubes attracts...

Scientists celebrated at the world's biggest atom smasher at the European Organization for Nuclear Research (CERN) near Geneva on Tuesday as they started colliding particles at record energy levels mimicking conditions close to the Big Bang, opening a new era in the quest for the secrets of the universe. The European Organisation for Nuclear Research (CERN) said it had unleashed the unprecedented bursts of energy on the third attempt, as beams of protons thrust around the 27-kilometre (16.8-mile) accelerator collided at close to the speed of light. "This is physics in the making, the beginning of a new era, we...

Largest ever object put into quantum state.A team of scientists has succeeded in putting an object large enough to be visible to the naked eye into a mixed quantum state of moving and not moving. Andrew Cleland at the University of California, Santa Barbara, and his team cooled a tiny metal paddle until it reached its quantum mechanical 'ground state' — the lowest-energy state permitted by quantum mechanics. They then used the weird rules of quantum mechanics to simultaneously set the paddle moving while leaving it standing still. The experiment shows that the principles of quantum mechanics can apply...

In today's technological age, it might seem silly for intelligent people to consider a spiritual world where beings we cannot see might exist. Oh it's fine to read books and watch Hollywood movies about the afterlife and spirits that roam the netherworld but that's all make believe, not the real world. In the real world we are taught that reality consists of what we can touch, taste, see, hear, smell, and that the spirit world is for those weak minded individuals who use religion as a crutch to get through the day.  However, what if I told you that...

The typical Hollywood action hero skirts death for a living. Time and again, scores of bad guys shoot at him from multiple directions but miss by a hair. Cars explode just a fraction of a second too late for the fireball to catch him before he finds cover. And friends come to the rescue just before a villain’s knife slits his throat. If any one of those things happened just a little differently, the hero would be hasta la vista, baby. Yet even if we have not seen the movie before, something tells us that he will make it to...

GENEVA – The world's largest atom smasher has recorded its first high-energy collisions of protons, a spokeswoman said Wednesday. Physicists hope those collisions will help them understand suspected phenomena such as dark matter, antimatter and ultimately the creation of the universe billions of years ago, which many theorize occurred as a massive explosion known as the Big Bang. The collisions occurred Tuesday evening as the Large Haldron Collider underwent test runs in preparation for operations next year, said Christine Sutton of the European Organization for Nuclear Research, or CERN. Two beams of circulating particles traveling in opposite directions at 1.18...

Shortly after the first of the year (if not already), the Large Hadron Collider — the most powerful particle accelerator ever built — will smash protons together at record energies. If the Earth remains intact, doomsayers will once again have been falsified. Every time they forecast the demise of the planet, those prophets of Earthly annihilation prove themselves no more foresightful than mortgage bankers or phony psychics.

Was Newton right and Einstein wrong? It seems that unzipping the fabric of spacetime and harking back to 19th-century notions of time could lead to a theory of quantum gravity. Physicists have struggled to marry quantum mechanics with gravity for decades. In contrast, the other forces of nature have obediently fallen into line. For instance, the electromagnetic force can be described quantum-mechanically by the motion of photons. Try and work out the gravitational force between two objects in terms of a quantum graviton, however, and you quickly run into trouble—the answer to every calculation is infinity. But now Petr Hořava,...

Today the John Templeton Foundation announced the winner of the annual Templeton Prize of a colossal £1 million ($1.4 million), snip D'Espagnat boasts an impressive scientific pedigree, having worked with Nobel laureates Louis de Broglie, Enrico Fermi and Niels Bohr. De Broglie was his thesis advisor; he served as a research assistant to Fermi; and he worked at CERN when it was still in Copenhagen under the direction of Bohr. snip Third view Unlike classical physics, d'Espagnat explained, quantum mechanics cannot describe the world as it really is, it can merely make predictions for the outcomes of our observations. If...

Science fiction looks closer to becoming science fact. Parallel universes really do exist, according to a mathematical discovery by Oxford scientists that sweeps away one of the key objections to the mind boggling and controversial idea. The work has wider implications since the idea of parallel universes sidesteps one of the key problems with time travel. Every since it was given serious lab cred in 1949 by the great logician Kurt Godel, many eminent physicists have argued against time travel because it undermines ideas of cause and effect to create paradoxes: a time traveller could go back to kill his...

Harvard University researchers have halted a pulse of laser light in its tracks and revived it a fraction of a millimeter away. Here's the twist: they stopped it in a cloud of supercold sodium atoms, known as a Bose-Einstein condensate (BEC), and then restarted it in a second, distinct BEC as though the pulse had spookily jumped between the two locations. "It's odd," says atomic physicist Lene Hau, the team's leader. "We can actually revive the light pulse and send it back on its way as if nothing had happened." ~snip~ BEC clouds are prized because their atoms' delicate quantum...

Why Quantum Mechanics Is Not So Weird after All Richard Feynman's "least-action" approach to quantum physics in effect shows that it is just classical physics constrained by a simple mechanism. When the complicated mathematics is left aside, valuable insights are gained. PAUL QUINCEY The birth of quantum mechanics can be dated to 1925, when physicists such as Werner Heisenberg and Erwin Schrödinger invented mathematical procedures that accurately replicated many of the observed properties of atoms. The change from earlier types of physics was dramatic, and pre-quantum physics was soon called classical physics in a kind of nostalgia for the...

...Bohm showed that Einstein was partly right in that Bohr's view was incomplete. One must keep both the particles and force fields of the old physics in addition to the new quantum wave function. Contrary to Bohr, we can picture the motion of particles in space at the quantum level , but there is a new kind of quantum force in addition to the classical forces of electromagnetism, gravity and even the strong and weak forces of modern high energy physics. This new quantum force or "connection" is like The Force in George Lucas's Star Wars. Unlike ordinary forces the...

December 27, 2005 Quantum Trickery: Testing Einstein's Strangest Theory By DENNIS OVERBYE Einstein said there would be days like this.This fall scientists announced that they had put a half dozen beryllium atoms into a "cat state."No, they were not sprawled along a sunny windowsill. To a physicist, a "cat state" is the condition of being two diametrically opposed conditions at once, like black and white, up and down, or dead and alive.These atoms were each spinning clockwise and counterclockwise at the same time. Moreover, like miniature Rockettes they were all doing whatever it was they were doing together, in...

At a physics meeting last October, Nobel laureate David Gross outlined 25 questions in science that he thought physics might help answer. Nestled among queries about black holes and the nature of dark matter and dark energy were questions that wandered beyond the traditional bounds of physics to venture into areas typically associated with the life sciences. One of the Gross's questions involved human consciousness. He wondered whether scientists would ever be able to measure the onset consciousness in infants and speculated that consciousness might be similar to what physicists call a "phase transition," an abrupt and sudden large-scale transformation...

Interview with Martin Gardner Martin Gardner occupies a unique position in the mathematical world. The author of the “Mathematical Games” column that ran for twenty-five years in Scientific American magazine, he opened the eyes of the general public to the beauty and fascination of mathematics and inspired many to go on to make the subject their life’s work. His column was the place where several important mathematical notions, such as Conway’s Game of Life and Penrose tiles, first became widely known. It was also a place where the sheer fun of mathematical games and puzzles was celebrated and savored....