Related papers: Instanton in Disordered Peierls Systems
The electron spectrum in the normal phase of cuprates is analyzed in terms of the boson-fermion model. It is argued that the existence of the uncondensed pairs and the quasi-two-dimensional nature of the crystal structure are responsible…
We study the level-statistics of a disordered system undergoing the Anderson type metal-insulator transition. The disordered Hamiltonian is a sparse random matrix in the site representation and the statistics is obtained by taking an…
Peierls-type instabilities in quarter-filled ($\bar{n}=1/2$) and half-filled ($\bar{n}=1$) quantum double-well hydrogen-bonded chain are investigated analytically in the framework of two-stage orientational-tunnelling model with additional…
Coupled instantons are introduced by generalizing the double well potential to multiple mutually coupled wells. Physically this corresponds to the simultaneous tunneling of multiple degrees of freedom. A system with four equal minima is…
The normal state behaviour of the density of states of the electrons described by the BOSON - FERMION model for Bose-Einstein condensation driven superconductivity is characterized by the appearence of a pseudogap which developes into a…
Using the vanishing of the typical polaron tunneling rate as an indicator of the breakdown of itinerancy, we study the localization of polaron states in a generic model for a disordered polaronic material. We find that extremely small…
This work extends the applications of Anderson-type Hamiltonians to include transport characterized by anomalous diffusion. Herein, we investigate the transport properties of a one-dimensional disordered system that employs the discrete…
I study the effect of Coulomb interaction on superconducting order in a d-wave lattice superconductor at T=0 by considering the superconducting saddle point in the two dimensional t-J-U model with an on-site repulsion U. The theory of low…
We measure the statistical distribution of the local density of optical states (LDOS) on disordered semi-continuous metal films. We show that LDOS fluctuations exhibit a maximum in a regime where fractal clusters dominate the film surface.…
Recent study demonstrated that steady states of a polariton system may show a first-order dissipative phase transition with an exceptional point that appears as an endpoint of the phase boundary [R. Hanai et al., Phys. Rev. Lett. 122,…
We review the phenomenon of equilibrium fluctuations in the number of condensed atoms in a trap containing N atoms total. We start with a history of the Bose-Einstein distribution, the Einstein-Uhlenbeck debate concerning the rounding of…
The dissociation of excited electron-hole pairs is a microscopic process that is fundamental to the performance of photovoltaic systems. For this process to be successful, the oppositely charged electron and hole must overcome an…
Alkaline-earth like atoms with ultra-narrow optical transitions enable superradiance in steady state. The emitted light promises to have an unprecedented stability with a linewidth as narrow as a few millihertz. In order to evaluate the…
We propose to combine the Floquet formalism for systems in ac fields with the dynamical mean-field theory to study correlated electron systems periodically driven out of equilibrium by external fields such as intense laser light. This…
The normal state of the recently discovered Iron Selenide (FeSe)-based superconductors shows a range of inexplicable features. Along with bad-metallic resistivity, characteristic pseudogap features and proximity to insulating states,…
Light-matter interactions are known to lead to the formation of polariton states through what is called strong coupling, leading to the formation of two hybrid states usually tagged as Upper and Lower Polaritons. Here, we consider a similar…
The development of patterned multi-quantum well heterostructures in GaAs/AlGaAs waveguides has recently allowed to achieve exciton-polariton condensation in a topologically protected bound state in the continuum (BIC). Remarkably,…
One-particle spectral properties in the normal phase of the two-dimensional attractive Hubbard model are investigated in the weak coupling regime using the non-selfconsistent T-matrix approximation. The corresponding equations are evaluated…
The presence of a permanent electric dipole moment in an elementary particle implies Charge-Parity symmetry violation and thus could help explain the matter-antimatter asymmetry observed in our universe. Within the context of the Standard…
Normal state superconducting fluctuations are calculated for the case of a tight binding bandstructure. The resulting electronic self energy and spectral weight are anisotropic on the Fermi surface. For certain values of the chemical…