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Topic: Fermion condensate

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In the News (Sun 21 Apr 19)

  Fermionic condensate - Wikipedia, the free encyclopedia
The earliest recognized fermionic condensate described the state of electrons in a superconductor; the physics of other examples including recent work with fermionic atoms is analogous.
A chiral condensate is an example of a fermionic condensate that appears in theories of massless fermions with chiral symmetry breaking.
The primary difference between superfluid helium and a Bose-Einstein condensate is that the former is condensed from a liquid while the latter is condensed from a gas.
en.wikipedia.org /wiki/Fermion_condensate   (987 words)

The condensates in Fermi gases are generated with "Feshbach resonance", which allows the size of the pairs to be varied from much larger than the mean distance between atoms to about the size of an atom.
Fermions are particles whose intrinsic angular momentum (or spin) is an odd multiple of h/2(pi), where (h) is the Planck constant.
The fermions are arranged in the trap in a cloud with relatively large spatial distribution and large kinetic energy, which can be interpreted as being the result of an outward "Fermi pressure" (2,3).
scienceweek.com /2004/sa040924-6.htm   (1277 words)

 BEC I our papers   (Site not responding. Last check: 2007-10-31)
The observable was the fraction of condensed molecules in the cloud after a rapid magnetic field ramp across the Feshbach resonance.
Condensate fractions were determined from the molecular cloud, and the numbers in each component were recorded.
Emergence of a Bose-Einstein condensate of atom pairs as the temperature was lowered.
cua.mit.edu /ketterle_group/experimental_setup/BEC_I/our_papers.html   (712 words)

 NIST/University of Colorado Scientists Create New Form of Matter: A Fermionic Condensate
Bose-Einstein condensates are collections of thousands of ultracold particles occupying a single quantum state, that is, all the atoms are behaving identically like a single, huge superatom.
Bose-Einstein condensates are made with bosons, a class of particles that are inherently gregarious; they’d rather adopt their neighbor’s motion than go it alone.
Fermions have half-integer “spins” (1/2, 3/2, 5/2, etc.), while bosons have integer “spins” (1, 2, 3, etc.).
www.nist.gov /public_affairs/releases/fermi_condensate.htm   (1235 words)

 NIST/University of Colorado researchers create Bose-Einstein 'super molecule'
Fermions are a class of particles that are inherently difficult to coax into a uniform quantum state.
Jin describes her team's work as the "first molecular condensate" and says it is closely related to "fermionic superfluidity," a hotly sought after state in gases that is analogous to superconductivity in metals.
While fermionic superfluidity was not demonstrated in the current experiments, the NIST/CU-Boulder authors note that their molecular condensate was produced by passing through the appropriate conditions for fermionic superfluidity.
www.eurekalert.org /pub_releases/2003-11/nios-noc112003.php   (912 words)

 Color superconductivity - Wikipedia, the free encyclopedia
Color superconducting phases are to be contrasted with the normal phase of quark matter, which is just a weakly-interacting Fermi liquid of quarks.
In theoretical terms, a color superconducting phase is a state in which the quarks near the Fermi surface become correlated in Cooper pairs, which condense.
The fact that a Cooper pair of quarks carries a net color charge, as well as a net electric charge, means that the gluons (which mediate the strong interaction just as photons mediate electromagnetism) become massive in a phase with a condensate of quark Cooper pairs, so such a phase is called a "color superconductor".
en.wikipedia.org /wiki/Color_superconductivity   (1220 words)

 Physics News 671, January 30, 2004
Fermions (possessing half-integer spins, such as 1/2 or 3/2 or 9/2), whether elementary particles like electrons and quarks, or whole atoms (and in determining whether an atom is a boson or fermion one has to add up the spins of all its constituent protons, neutrons, and electrons), do not act like bosons.
In a quantum setting---whether electrons moving through a crystal or fermion atoms chilled in a trap, fermions are obliged to fill, one by one, all the different possible quantum energy states, starting at the low end.
This new condensed form of atomic matter should not be thought of merely as a way station between the BEC and (weak) BCS pairing alternatives, but as a unique state in its own right.
newton.ex.ac.uk /aip/physnews.671.html   (1231 words)

 CNN.com - U.S. scientists create new form of matter - Jan. 28, 2004
The new matter form is called a fermionic condensate and it is the sixth known form of matter -- after gases, solids, liquids, plasma and a Bose-Einstein condensate, created only in 1995.
Jin, a recent recipient of a MacArthur Foundation "genius grant," was building on the discovery of the Bose-Einstein condensate by her colleagues Eric Cornell and Carl Wieman.
Bose-Einstein condensates are collections of thousands of ultracold particles that occupy a single quantum state -- they all essentially behave like a single, huge superatom.
edition.cnn.com /2004/TECH/science/01/28/matter.new.reut/index.html   (615 words)

 Statistical mechanics - Wikipedia, the free encyclopedia
In most condensed matter systems, things are nonrelativistic and mass is conserved.
However, most condensed matter systems of interest also conserve particle number approximately (metastably) and the mass (nonrelativistically) is none other than the sum of the number of each type of particle times its mass.
Mass is inversely related to density, which is the conjugate variable to pressure.
en.wikipedia.org /wiki/Statistical_Mechanics   (2425 words)

 UH -Top Education Stories - Rice superfluid lab is one of five in the world that can make it
In the last decade, scientists have gotten increasingly good at creating condensates — essentially supercooled gases in which thousands or more atoms are squeezed into a single quantum state.
The problem with fermions, though, is that they are defined by the fact that they cannot occupy the same quantum state.
Creating a condensate of fermions is important to physicists because the condensate becomes a "superfluid" with no viscosity at extremely low temperatures.
www.uh.edu /ednews/2004/hc/200412/20041221ricesuperfluid.html   (530 words)

 Alternate View Column AV-77
Fermions have half-integer spins and exhibit the territorial behavior described by the Pauli exclusion principle, with only one particle allowed in each quantum state.
The half-integer spin particles are called fermions because the statistics of their behavior in groups is governed by Fermi-Dirac statistics, as first described by Enrico Fermi and Paul Dirac.
If one fermion is in a particular quantum state, then all other fermions are excluded from that state, resulting in the Pauli exclusion principle.
www.npl.washington.edu /AV/altvw77.html   (2186 words)

 NIST/University of Colorado Scientists create new form of matter: A fermionic condensate
In 2001 JILA researcher Murray Holland and co-workers predicted that fermionic atom condensates would turn out to be the link between superconductivity and BECs.
It is this second, more subtle form of condensation that has been observed in the current experiments.
Instead, pairing of fermions is caused by the collective behavior of many atoms, similar to what causes "Cooper pairs" of electrons to form in a superconductor.
www.eurekalert.org /pub_releases/2004-01/nios-noc012704.php   (1216 words)

 Print the story
Image: A condensate of Fermion pairs (red) is trapped in the waist of a focussed Laser beam (pink).
The work is based on the MIT group's earlier creation of Bose-Einstein condensates, a form of matter in which particles condense and act as one big wave.
Bose-Einstein condensation of pairs of fermions that were bound together loosely as molecules was observed in November 2003 by independent teams at the University of Colorado at Boulder, the University of Innsbruck in Austria and at MIT.
www.physorg.com /printnews.php?newsid=4682   (888 words)

 KITP - 5
In which he introduced the concept of "Fermion condensation" as a way to understand the underlying order which develops at a heavy electron quantum critical point.
This power-law behavior is reminiscent of the observed properties of heavy fermions.
The plight of the fermion condensate is however, one that is shared by any model of the quantum critical point that purports to develop localized fermionic modes.
www.kitp.ucsb.edu /activities/qpt05/blog/5   (1658 words)

 ScienceDaily: NIST/University Of Colorado Scientists Create New Form Of Matter: A Fermionic Condensate
NIST/University Of Colorado Scientists Create New Form Of Matter: A Fermionic Condensate (January 29, 2004) -- Scientists at JILA, a joint laboratory of the Department of Commerce's National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder (CU-Boulder) report the first...
Nobel Prize In Physics Goes To Discovers Of New State Of Matter: Bose-Einstein Condensate (October 9, 2001) -- The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics for 2001 jointly to Eric A. Cornell, of JILA and the National Institute of Standards and Technology (NIST) in...
Bose—Einstein condensate -- A Bose-Einstein condensate is a phase of matter formed by bosons cooled to temperatures very near to absolute...
www.sciencedaily.com /releases/2004/01/040129073547.htm   (2472 words)

 Highbeam Encyclopedia - Search Results for fermion   (Site not responding. Last check: 2007-10-31)
fermion FERMION [fermion] : see elementary particles ; exclusion principle ; Fermi-Dirac statistics.
Heat Response Provides Evidence for High Temperature Superfluidity in Cold 'Fermion' Gas.
Rice University lab makes major breakthrough with fermion condensate.
www.encyclopedia.com /SearchResults.aspx?Q=fermion   (147 words)

 Truth Quark, Higgs, and Vacua
Michio Hashimoto, Masaharu Tanabashi, and Koichi Yamawaki in their paper at hep-ph/0311165 describe a T-quark condensate models in 8-dimensional spacetime (with 4 compact dimensions) that seem to be related to the
The chiral condensation of bulk fermions may generate dynamically a composite Higgs field, instead.
With respect to spinor fermions and spin structure, even though CP2 is not a spin manifold, it is a spin_c (complex) manifold as described in the book Spin Geometry by Lawson and Michelsohn (Princeton 1989) particularly page 392.
www.valdostamuseum.org /hamsmith/YamawakiCP2KKNJL.html   (5662 words)

 Notes to Symmetry and Symmetry Breaking
More recently, new symmetries acquired relevance in theoretical physics, such as supersymmetry (the symmetry relating bosons and fermions and leading, when made local, to the theories of supergravity), and the various forms of duality used in today’s superstring theories.
In the BCS theory of superconductivity, as well as in the 1961 theory of broken chiral symmetry by Nambu and Jona-Lasino, SSB is realized dynamically through a fermion condensate.
In the BCS theory, for example, the gauge invariance of electromagnetism is spontaneously broken by pairs of electrons that condense -- forming a bound state -- in the ground state of a metal.
plato.stanford.edu /entries/symmetry-breaking/notes.html   (735 words)

 Fermion condensate model of electroweak interactions
Two fermions of different SU (2) representations form a symmetry breaking condensate and generate the lepton and quark masses.
The weak gauge bosons obtain their usual standard model masses from a gauge-invariant Lagrangian of a doublet scalar field composed of the new fermion fields.
It is shown that the new charged fermions are produced at the next linear colliders in large number.
www.edpsciences.org /10.1140/epjc/s2006-02512-0   (168 words)

 Jin page   (Site not responding. Last check: 2007-10-31)
We have recently observed condensation of fermionic atom pairs in the BCS-BEC crossover regime.
In order to search for condensation on either side of the resonance we introduce a technique that pairwise projects fermionic atoms onto molecules; this enables us to measure the momentum distribution of fermionic atom pairs.
The transition to condensation of fermionic atom pairs is mapped out as a function of the initial atom gas temperature T compared to the Fermi temperature T
jilawww.colorado.edu /~jin   (225 words)

 Physics Papers
Further, the desired chiral properties are seen for the chiral condensate, suggesting that the domain wall fermion formulation may be an effective approach for the numerical study of QCD at finite temperature.
One of the major frontiers of lattice field theory is the inclusion of light fermions in simulations, particularly in pursuit of accurate, first principles predictions from lattice QCD.
In this talk, we report on extensive studies of the domain wall formulation of lattice fermions, which avoids this difficulty at the expense of requiring that fermion propagators be computed in five dimensions.
phys.columbia.edu /~cqft/physics_papers.htm   (1894 words)

 NIST/University of Colorado Scientists Create New Form of Matter: A Fermionic Condensate | News Center | University of ...
Unlike bosons, fermions -- the other half of the particle family tree and the basic building blocks of matter -- are inherently loners.
Consequently, to a physicist even the term -- fermionic condensate -- is almost an oxymoron.
“We expect that the fermionic condensates that we observed,” notes Jin, “will exhibit superfluid behavior.
www.colorado.edu /news/releases/2004/21.html   (1283 words)

 SCES 2001- Non-Fermi Liquids, Quantum Critical Points, and Hidden Order #3
A model of a Fermi liquid with the fermion condensate is applied to the consideration of quasiparticle excitations in high temperature superconductors, in their superconducting and normal states.
Within our model the appearance of the fermion condensate presents a quantum phase transition, that separates the regions of normal and strongly correlated electron liquids.
Arguments are presented that fermion systems with the fermion condensate have features of a quantum protectorate.
www.neutron.anl.gov /sces2001/program/0237   (218 words)

 NIST/University of Colorado Scientists create new form of matter: A fermionic condensate   (Site not responding. Last check: 2007-10-31)
Finally a pairing of fermionic atoms is shown to turn into bosonic substance (as it should)
It has long been known that a pair of fermions (each spin 1/2), if intimate enough, should act like a boson (integral spin).
That's because a fully-linked pair of fermions will act like a particle of spin 0 (if they pair according to 69) or spin 1 (if they pair in the missionary position).
www.freerepublic.com /focus/f-news/1067101/posts   (2778 words)

 NORDITA-96/63 P hep-ph/9610270 October 7, 1996 (ResearchIndex)   (Site not responding. Last check: 2007-10-31)
Any boundary state that has an overlap with the true QCD ground state generates a perturbative series that (when summed to all orders) is formally exact.
Through an analogy with the boundary condition corresponding to a fermion condensate, I propose an explicit form for a `perturbative gluon condensate' that suppresses low momentum...
0.2: Kinetic equations in the presence of a Bose-Einstein condensate - Fauser (1996)
citeseer.ist.psu.edu /178531.html   (289 words)

 Citebase - Instantons and fermion condensate in adjoint QCD2   (Site not responding. Last check: 2007-10-31)
At high temperatures, quasiclassical approximation works and the action and the form of effective (with account of quantum corrections) instanton solution can be evaluated.
There are 2(N-1) fermion zero modes in the instanton background which implies the absence of the condensate in the massless limit.
Possible ways to resolve this paradox (which occurs also in some 4-dim gauge theories) are discussed.
citebase.eprints.org /cgi-bin/citations?id=oai:arXiv.org:hep-th/9402066   (189 words)

 [No title]   (Site not responding. Last check: 2007-10-31)
The second analysis is made only with the fermionic degrees of freedom.
Since the sum-rule for the fermion condensate is not derived within the conventional light-front quantization, it is important to check the validity of it.
We examine the effects in the Schwinger model and obtain consistent results with those of the classical reduction after redefinitions of the fermion currents.
quark.phy.bnl.gov /~itakura/thesis.html   (402 words)

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