597 research outputs found
Aspects of unconventional density waves
Recently many people discuss unconventional density waves (i.e.
unconventional charge density waves (UCDW) and unconventional spin density
waves (USDW)). Unlike in conventional density waves, the quasiparticle spectrum
in these systems is gapless. Also these systems remain metallic. Indeed it
appears that there are many candidates for UDW. The low temperature phase of
alpha-(BEDT-TTF)_2KHg(SCN)_4, the antiferromagnetic phase in URu_2Si_2, the CDW
in transition metal dichalcogenite NbSe_2, the pseudogap phase in high T_c
cuprate superconductors, the glassy phase in organic superconductor
kappa-(BEDT-TTF)_2Cu[N(CN)_2]Br. After a brief introduction on UCDW and USDW,
we shall discuss some of the above systems, where we believe we have evidence
for unconventional density waves.Comment: 11 pages, 5 figure
Abrikosov Vortex and Branes
We give a brief review of the application of some topological solutions in
field theory.Comment: To appear in a volume in honour of A.P.Balchandran in occasion of his
65th birthday. Spelling of the name in the title and some other typos
correcte
Optical Conductivity in the Copper Oxide Materials
The frequency- and temperature-dependent optical conductivity of the copper
oxide materials in the underdoped and optimal doped regimes are studied within
the t-J model. The conductivity spectrum shows the unusual behavior at low
energies and anomalous midinfrared peak in the low temperatures. However, this
midinfrared peak is severely depressed with increasing temperatures, and
vanishes at higher temperatures.Comment: 11 pages, Revtex, Two figures are not included, and can be obtained
by reques
Rochelle salt: a prototype of particle physics
Rochelle salt has a remarkable characteristic of becoming more ordered for a
range of high temperatures before melting. In the particle physics language
this means more symmetry breaking for high T. In many realistic field theories
this is a perfectly consistent scenario which has profound consequences in the
early universe. In particular it implies that there may be no domain wall and
monopole problems, and it may also play an important role in baryogenesis if CP
and P are broken spontaneously. In the case of the monopole problem this may
require a large background charge of the universe. The natural candidates for
this background charge are a possible lepton number in the neutrino sea or
global continous R-charges in supersymmetric theories.Comment: 9 pages, uses sprocl.sty, plenary talk given at the International
Workshop COSMO97 on Particle Physics and the Early Universe, 15-19 September
1997, Ambleside, Lake District, England, to be published in the Proceedings.
References adde
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