Richard Feynman on Quantum Mechanics - Part 1 - Photons: Corpusc. Black-hole like effect in nanotube and the possibility of new ma. (PhysOrg.com) -- “For the first time, fields of study relating both to cold atoms and to the nanoscale have intersected,” Lene Vestergaard Hau tells PhysOrg.com. “Even though both have been active areas of research, cold atoms have not been brought together with nanoscale structures at the single nanometer level. This is a totally new system.” Hau is the Mallinckrodt Professor of Physics and Applied Physics at Harvard University.
Along with colleague J.A. “What we observed has a number of interesting fundamental and practical implications,” Hau says. In order to create the effect, Hau and her team grew a single-walled carbon nanotube in their lab. Once captured, an atom begins on a spiraling path, orbiting more and more rapidly, until it is ripped apart very close to the nanotube.
“When the electron is pulled in, it goes through a tunneling process,” Hau explains. Another possibility is that this combination of cold atoms with nanoscale structures could lead to new states of matter. Masses of common quarks are revealed. (PhysOrg.com) -- A research group co-founded by Cornell physics professor G. Peter Lepage has calculated the mass of the three lightest and, therefore, most elusive quarks: up, down and strange. Quarks, the elementary particles that make up protons and neutrons, have been notoriously difficult to nail down -- much less weigh -- until now. A research group co-founded by Cornell physics professor G. Peter Lepage has calculated, with a razor-thin margin of error, the mass of the three lightest and, therefore, most elusive quarks: up, down and strange. The work of Lepage, the Harold Tanner Dean of the College of Arts and Sciences, and collaborators from several international institutions, is published online (March 31) and in print in Physical Review Letters (Vol. 104:13).
The findings reduce the uncertainty of the quark masses by 10 to 20 times down to a few percent. To determine the quark masses, Lepage explained, it was necessary to fully understand the strong force. Glasgow scientists predict mass of new particle. (PhysOrg.com) -- A team of physicists from the University of Glasgow has predicted the mass of a new particle which would help explain one of the fundamental forces of the universe.
The scientists say the Bc* meson will have been produced fleetingly in collisions in the Tevatron accelerator in Illinois, USA and at CERN in Switzerland, but has not yet been spotted by experimentalists searching through the debris. However, a team led by Professor Christine Davies, head of the University's Particle Physics Theory Group in the Department of Physics and Astronomy, and an expert in Quantum Chromodynamics (QCD) theory, used supercomputers to predict the mass of the meson, which might help scientists understand the strong force that dictates the behaviour of particles at the sub-atomic level. The strong force is one of the four fundamental forces of the universe and is what holds quarks together - the smallest units of matter found to date.
It is this force that QCD theory seeks to understand. MIT physicist to describe strange world of quarks, gluons. One of the great theoretical challenges facing physicists is understanding how the tiniest elementary particles give rise to most of the mass in the visible universe. Tiny particles called quarks and gluons are the building blocks for larger particles such as protons and neutrons, which in turn form atoms. However, quarks and gluons behave very differently than those larger particles, making them more difficult to study.
John Negele, the W.A. Coolidge Professor of Physics at MIT, will talk about the theory that governs interactions of quarks and gluons, known as quantum chromodynamics (QCD), during a Feb. 17 presentation to the American Association for the Advancement of Science annual meeting in Boston. Negele will describe how scientists are using supercomputers and a concept called lattice field theory to figure out the behavior of quarks and gluons, the smallest known particles. Molecules are built from atoms, atoms from electrons and nuclei, and nuclei from protons and neutrons. Latest Supercomputer Calculations Support the Six-Quark Theory. A new calculation, reported in the January 25, 2008 issue of Physical Review Letters, confirms the six-quark theory of particle-anti-particle asymmetry.
This is the first complete calculation of this phenomenon to employ a highly accurate description of the quarks that adds a fifth dimension beyond those of space and time. This result allows recent experiments studying the decays of bottom quarks to be compared with earlier, strange quark experiments. This comparison agrees with the predictions of the Standard Model of particle physics and implies that the particle-anti-particle asymmetries (technically known as "CP-symmetry violation") seen in these two different decay processes have a common origin. This research was carried by physicists from the U.S. Earth, our solar system, our galaxy - and likely the entire visible universe - are made of matter, not anti-matter. Accommodating such a matter-anti-matter asymmetry into a fundamental theory is not easy.
Physicist proposes method to teleport energy. (PhysOrg.com) -- Using the same quantum principles that enable the teleportation of information, a new proposal shows how it may be possible to teleport energy. By exploiting the quantum energy fluctuations in entangled particles, physicists may be able to inject energy in one particle, and extract it in another particle located light-years away.
The proposal could lead to new developments in energy distribution, as well as a better understanding of the relationship between quantum information and quantum energy. Japanese physicist Masahiro Hotta of Tohoku University has explained the energy teleportation scheme in a recent study posted at arxiv.org, called “Energy-Entanglement Relation for Quantum Energy Teleportation.”
Previously, physicists have demonstrated how to teleport the quantum states of several different entities, including photons, atoms, and ions. In quantum energy teleportation, a physicist first makes a measurement on each of two entangled particles. Long-distance quantum communication gets closer as physicists in. (PhysOrg.com) -- In a new demonstration of reversible light storage, physicists have achieved storage efficiencies of more than a magnitude greater than those offered by previous techniques. The new method could be useful for designing quantum repeaters, which are necessary for achieving long-distance quantum communication. Physicists Thierry Chaneličre of the Laboratoire Aimé Cotton - CNRS in Orsay, France, and his coauthors have published their results of the new light storage method in a recent issue of the New Journal of Physics. The new technique involves mapping a light field onto a thulium-doped crystal. Compared with other kinds of rare-earth ions, thulium has an interaction wavelength that makes it more easily accessible with laser diodes, allowing for a better preparation of the tool used to store the light - an atomic frequency comb.
“The efficiency is the probability of retrieval,” Chaneličre explained. Explore further: Progress in the fight against quantum dissipation. Proposed test of weak equivalence principle could be most accura. (PhysOrg.com) -- The weak equivalence principle (WEP) - which states that all bodies fall at the same rate in a gravitational field, regardless of structure or composition - is one of the key postulates of general relativity. Tests have shown that the WEP is accurate to within one part in 10 trillion, or an uncertainty of 10-13 of the acceleration of gravity. However, a violation of the WEP is suggested by most theories that attempt to unify gravity with the other forces, which is one of the biggest challenges in physics today. Looking for new ways to test the WEP to even greater accuracy and perhaps detect a violation, astrophysicists at the Harvard-Smithsonian Center for Astrophysics have designed a new WEP test to be conducted during free fall in a rocket flight.
One way that scientists can test the WEP is by measuring the accelerations of two bodies made of different materials falling in the same gravitational field. In their proposed experiment, Dr. Reasenberg and Dr.