Escape from a metastable potential is considered on time-scales less than are needed for the creation of quasi-equilibrium within the well. It is shown that the escape flux may then depend exponentially strongly, and in a complicated way, on friction and time.

1. Evolution of a physical system can be ordered in multi-timescales. Details of evolution on short-time-scale do not need for description in a closed form of a system evolution on long-time-scale and appears on this scale only in an average form. The prototype of such kind physical systems is dissipative Brownian motion of a particle in an external potential field. In this problem, with the ex...

We examine the effect of subdividing the potential barrier along the reaction coordinate on Kramers’ escape rate for a model potential. Using the known supersymmetric potential approach, we show the existence of an optimal number of subdivisions that maximises the rate.

A general expression for the semiclassical, nonrelativistic linear polarizability of an arbitrary volume element V has been derived in the long wavelength approximation. The derivation starts from the expectation value of the dipole strength, as in the original Kramers-Heisenberg paper about optical scattering by atoms. The main requirements underlying the present approach are a separate non-He...

Utilizing a complete Lorentz-covariant and local-gauge-invariant formulation, we discuss graphene response to arbitrary external electric field. The relation, which is called as Kramers-Krönig relation in the paper, between imaginary part and real part of ac conductivity is given. We point out there exists an ambiguity in the conductivity computing, attributed to the wick behavior at ultraviole...

We offer fairly simple and direct proofs of the asymptotics for the scaled Kramers-Smoluchowski equation in both one and higher dimensions. For the latter, we invoke the sharp asymptotic capacity asymptotics of Bovier–Eckhoff–Gayrard–Klein [B-E-G-K].

Marcello Sega, Pietro Faccioli, 3 Francesco Pederiva, 4 and Henri Orland Frankfurt Institute for Advanced Studies, Ruth-Moufang-Str. 1, D-60435 Frankfurt, Germany∗ Dipartmento di Fisica, Università di Trento, Via Sommarive 14, I-38050 Povo (Trento), Italy I.N.F.N Gruppo Collegato di Trento I.N.F.M-Democritos, National Simulation Center, Trieste, Italy Service de Physique Théorique, Centre d’Etu...

Experimental identification of quantum spin ice (QSI), a U(1) liquid on the pyrochlore lattice hosting emergent photons, is major challenge in frustrated magnets. In this work, we propose ultrasound measurements as novel tool for probing photons various QSI phases. Our analysis includes phases non-Kramers doublet compounds such $\rm{Pr}_2 \rm{Zr}_2 \rm{O}_7$ well dipolar-octupolar Kramers $\rm{...