Generalized Gibbs Ensemble of 2D CFTs with U(1) charge from the AGT correspondence

The Generalized Gibbs Ensemble (GGE) is relevant to understand the thermalization of quantum systems with an infinite set of conserved charges. In this work, we analyze the GGE partition function of 2D Conformal Field Theories (CFTs) with a U(1) charge and quantum Benjamin-Ono2 (qBO2) hierarchy charges. We use the Alday-Gaiotto-Tachikawa (AGT) correspondence to express the thermal trace in terms of the Alba-Fateev-Litvinov-Tarnopolskiy (AFLT) basis of descendants, which diagonalizes all charges. We analyze the GGE partition function in the thermodynamic semiclassical limit, including the first order quantum correction. We find that the equality between GGE averages and primary eigenvalues of the qBO2 charges is attainable in the strict large c limit and potentially violated at the subleading 1/c order. We also obtain the finite c partition function when only the first non-trivial charge is turned on, expressed in terms of partial theta functions. Our results should be relevant to the eigenstate thermalization hypothesis for charged CFTs, Warped CFTs and effective field theory descriptions of condensed matter systems.

Gibbs-ensemble Monte Carlo simulations for binary mixtures

<p>We explore the performance of the Gibbs-ensemble Monte Carlo simulation method by calculating the miscibility gap of H<sub>2</sub>-He mixtures with analytical exponential-six potentials [1]. We calculate demixing curves for pressures up to <em>500</em> kbar and temperatures up to <em>1800</em> K. Our results are in good agreement with <em>ab initio </em>simulations in the non-dissociated region of the phase diagram. Next, we determine new parameters for the Stockmayer potential [2] to model the interactions in the H<sub>2</sub>O-H<sub>2</sub>O system for temperatures of <em>1000</em> K < <em>T</em> < <em>2000</em> K. The corresponding miscibility gap of H<sub>2</sub>-H<sub>2</sub>O mixtures was determined and we calculated demixing curves for pressures up to <em>150</em> kbar and temperatures up to <em>2000</em> K. Our results show reasonable agreement with previous experimental data of Bali <em>et al.</em> [3]. These results are important for interior and evolution models for ice giant planets [4].<br><br><strong>References</strong><br>[1] A. Bergermann, M. French, M. Schöttler and R. Redmer, Phys. Rev. E, 103 (2021)<br>[2] W. Stockmayer, The Journal of Chemical Physics 9, S. 398-402 (1941)<br>[3] E. Bali, A. Audétat and H. Keppler, Nature, 495, 7440 (2013)<br>[4] R. Helled, N. Nettelmann and T. Guillot, Space Science Reviews, 216 (2020)<br><br><br><br><br></p>

Signature of Generalized Gibbs Ensemble Deviation from Equilibrium: Negative Absorption Induced by a Local Quench

When a parameter quench is performed in an isolated quantum system with a complete set of constants of motion, its out of equilibrium dynamics is considered to be well captured by the Generalized Gibbs Ensemble (GGE), characterized by a set {λα} of coefficients related to the constants of motion. We determine the most elementary GGE deviation from the equilibrium distribution that leads to detectable effects. By quenching a suitable local attractive potential in a one-dimensional electron system, the resulting GGE differs from equilibrium by only one single λα, corresponding to the emergence of an only partially occupied bound state lying below a fully occupied continuum of states. The effect is shown to induce optical gain, i.e., a negative peak in the absorption spectrum, indicating the stimulated emission of radiation, enabling one to identify GGE signatures in fermionic systems through optical measurements. We discuss the implementation in realistic setups.

Gibbs-ensemble Monte Carlo simulation of H2–H2O mixtures

The miscibility gap in H2–H2O mixtures is investigated by conducting Gibbs-ensemble Monte Carlo simulations. Our results indicate that H2–H2O immiscibility regions may have a significant impact on the structure and evolution of ice giant planets.

Ab initio Gibbs ensemble Monte Carlo simulations of the liquid–vapor equilibrium and the critical point of sodium

We extend the application of the ab initio Gibbs ensemble method to the metallic system by including the contribution of excited electronic states.