相关论文: Quantum critical temperature of a modulated oscill…

We address the problem of identifying the critical temperature in a crossover from the Bose-Einstein condensed (BEC) phase to the normal phase. For this purpose we study the temperature dependence of magnetization of spin-gapped quantum…

We investigate bias-driven non-equilibrium quantum phase transitions in a paradigmatic quantum-transport setup: an interacting quantum dot coupled to non-interacting metallic leads. Using the Random Phase Approximation, which is exact in…

We study nonadiabatic electron transfer within the biased spin-boson model. We calculate the incoherent transfer rate in analytic form at all temperatures for a power law form of the spectral density of the solvent coupling. In the Ohmic…

Aim: We present an improved database of temperature dependent rate coefficients for rotational state-to-state transitions in H$_{2}$O + H$_{2}$O collisions. The database includes 231 transitions between the lower $para$- and 210 transitions…

Phase transitions of small isolated systems are signaled by the shape of the caloric equation of state e^*(T), the relationship between the excitation energy per nucleon e^* and temperature. In this work we compare the experimentally…

We present the effect of temperature on the switching characteristics of a bistable nonlinear nanomechanical beam. At MHz-range frequencies, we find that it is possible to controllably change the state of the system between two stable…

The phase transition in a 3D array of classical anharmonic oscillators with harmonic nearest-neighbour coupling (discrete $\phi^4$ model) is studied by Monte Carlo (MC) simulations and by analytical methods. The model allows to choose a…

In this chapter we discuss aspects of the quantum critical behavior that occurs at a quantum phase transition separating a topological phase from a conventionally ordered one. We concentrate on a family of quantum lattice models, namely…

The scaling of the transition temperature into an ordered phase close to a quantum critical point as well as the order parameter fluctuations inside the quantum critical region provide valuable information about universal properties of the…

A quasi-static process is realized in a purely quantum-mechanical model which is described by oscillator (or particle) systems having relative-phase interactions. Time development of a mixture of two oscillator (or particle) systems which…

We analyze the dynamics and final populations in a Landau-Zener problem for a two level system (or qubit) when this system interacts with one harmonic oscillator mode that is initially set to a finite-temperature thermal equilibrium state.…

The nature of quantum criticality in CeCoIn$_5$ is studied by low-temperature thermal expansion $\alpha(T)$. At the field-induced quantum critical point at H=5 T a crossover scale $T^\star\approx 0.3$ K is observed, separating…

It is generally believed that quantum fluctuations collaborate with thermal fluctuations, effectively reducing transition temperatures (e.g. for melting of charge order). We show that this is not always the case and that the interplay…

As spin-based quantum processors grow in size and complexity, maintaining high fidelities and minimizing crosstalk will be essential for the successful implementation of quantum algorithms and error-correction protocols. In particular,…

The superconductor-insulator transition (SIT) is considered an excellent example of a quantum phase transition which is driven by quantum fluctuations at zero temperature. The quantum critical point is characterized by a diverging…

We present a theoretical study of an escape rate for switching from the superconducting state to a resistive one in series arrays of strongly interacting Josephson junctions. At low temperatures such a switching is determined by macroscopic…

We develop a novel approach to phase transitions in quantum spin models based on a relation to their classical counterparts. Explicitly, we show that whenever chessboard estimates can be used to prove a phase transition in the classical…

Extending the temperature limits of quantum coherence in the system representing a chain of coupled two-level systems (TLS) exposed to an electromagnetic field is complicated due to the adverse influence of noise. Such a system frequently…

We consider a system of linear oscillators, or quantum states, described by Random Matrix Theory and analyze how its time evolution is affected by a nonlinear perturbation. Our numerical results show that above a certain chaos border a weak…

We consider thermal QCD in the large N_C limit, mainly in 1+1 dimensions. The gauge coupling is only taken into account to minimal order, by projection onto colour singlets. An expression for the free energy, exact as N_C goes to infinity,…