On the solution of an anisotropic nonquadratic potential

Jianming Cai, Akira Inomata

E. B. Gravador, M. Victoria Carpio-Bernido, Christopher Casenas Bernido

Marlon Brenes, Juan José Mendoza-Arenas, Archak Purkayastha +3 more

We present a methodology to simulate the quantum thermodynamics of thermal machines which are built from an interacting working medium in contact with fermionic reservoirs at a fixed temperature and chemical potential.Our method works at a finite temperature, beyond linear response and weak systemreservoir coupling, and allows for nonquadratic interactions in the working medium.The method uses mesoscopic reservoirs, continuously damped toward thermal equilibrium, in order to represent continuum baths and a novel tensor-network algorithm to simulate the steady-state thermodynamics.Using the example of a quantum-dot heat engine, we demonstrate that our technique replicates the well-known Landauer-Büttiker theory for efficiency and power.We then go beyond the quadratic limit to demonstrate the capability of our method by simulating a three-site machine with nonquadratic interactions.Remarkably, we find that such interactions lead to power enhancement, without being detrimental to the efficiency.Furthermore, we demonstrate the capability of our method to tackle complex many-body systems by extracting the superdiffusive exponent for high-temperature transport in the isotropic Heisenberg model.Finally, we discuss transport in the gapless phase of the anisotropic Heisenberg model at a finite temperature and its connection to charge conjugation parity, going beyond the predictions of single-site boundary driving configurations.

Scott H. Werden, Ernest R. Davidson

Andréa D Bertoldi, F. Minardi, M. Prevedelli

Atom interferometry is made more accurate by removing commonly employed approximations. A detailed model that includes the effect of Earth's gravitational potential and the duration of laser pulses is introduced, leading to interferometers with improved sensitivity.

Jonathan Keeling

Motivated by the experimental search for Bose condensation of quasiparticles in semiconductors, the response functions of a weakly interacting Bose gas, with isotropic but nonquadratic dispersion, are considered. Nonquadratic dispersion modifies the definition of particle current, and leads to modified sum rules for the current-current response function. The effect of these modifications on the Berezhinski-Kosterlitz-Thouless transition is discussed.