Random Hamiltonian in thermal equilibrium
نویسندگان
چکیده
A framework for the investigation of disordered quantum systems in thermal equilibrium is proposed. The approach is based on a dynamical model—which consists of a combination of a double-bracket gradient flow and a uniform Brownian fluctuation—that ‘equilibrates’ the Hamiltonian into a canonical distribution. The resulting equilibrium state is used to calculate quenched and annealed averages of quantum observables.
منابع مشابه
18.337 Project: A Random Walk with Julia
The characteristic vibrational modes of a physical system are determined by the potential energy term of the system’s Hamiltonian. These vibrations are of interest because of their properties govern thermal transport in semiconductors,The second order derivatives of the potential energy with respect to displacements about the equilibrium position of the atoms, colloquially referred to as the se...
متن کاملThe random geometry of equilibrium phases
2 Equilibrium phases 6 2.1 The lattice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.2 Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3 Observables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.4 Random fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.5 The Hamiltonian . . . . . ....
متن کاملBulk Properties of Anharmonic Chains in Strong Thermal Gradients: Non-Equilibrium φ Theory
We study nonequilibrium properties of a one-dimensional lattice Hamiltonian with quartic interactions in strong thermal gradients. Nonequilibrium temperature profiles, T (x), are found to develop significant curvature and boundary jumps. From the determination of the bulk thermal conductivity, we develop a quantitative description of T (x) including the jumps. PACs numbers: 05.70.Ln, 05.60.-k, ...
متن کاملThe Langevin Equation for a Quantum Heat Bath
We compute the quantum Langevin equation (or quantum stochastic differential equation) representing the action of a quantum heat bath at thermal equilibrium on a simple quantum system. These equations are obtained by taking the continuous limit of the Hamiltonian description for repeated quantum interactions with a sequence of photons at a given density matrix state. In particular we specialise...
متن کاملOn the local space-time structure of non-equilibrium steady states
We consider the Gibbs representation over space-time of non-equilibrium dynamics of Hamiltonian systems defined on a lattice with local interactions. We first write the corresponding action functional as a sum of local terms, defining a local action functional. We replace the local system by a translationinvariant system whose dynamics has an identical space-time characterization. We study in d...
متن کامل