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

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

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

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

Steepest decent method for a class of nonlinear equations

Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro,7, Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Interface magnetization effect in heterojunctions based on semimagnetic compounds

Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 , Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Emission of fermions from BTZ black holes

Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Weak-scale hidden sector and electroweak Q-balls

Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 , Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

The approximative Hamiltonian for the Dicce model defined in term one-zone potential

Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal