Thermodynamics and renormalized quasiparticles in the vicinity of the dilute Bose gas quantum critical point in two dimensions
| Autor: | Sebastian Eggert, Peter Kopietz, Dominik Strassel, Jan Krieg, Simon Streib |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Physics
Bose gas Quantum Monte Carlo FOS: Physical sciences Observable 01 natural sciences 010305 fluids & plasmas Renormalization Quantum Gases (cond-mat.quant-gas) Quantum critical point Quantum mechanics 0103 physical sciences Quasiparticle Functional renormalization group Condensed Matter - Quantum Gases 010306 general physics Boson |
| Zdroj: | Physical Review B, 95(2) |
| ISSN: | 2469-9950 |
| Popis: | We use the functional renormalization group (FRG) to derive analytical expressions for thermodynamic observables (density, pressure, entropy, and compressibility) as well as for single-particle properties (wavefunction renormalization and effective mass) of interacting bosons in two dimensions as a function of temperature $T$ and chemical potential $\mu$. We focus on the quantum disordered and the quantum critical regime close to the dilute Bose gas quantum critical point. Our approach is based on a truncated vertex expansion of the hierarchy of FRG flow equations and the decoupling of the two-body contact interaction in the particle-particle channel using a suitable Hubbard-Stratonovich transformation. Our analytic FRG results extend previous analytical renormalization group calculations for thermodynamic observables at $\mu =0$ to finite values of $\mu$. To confirm the validity of our FRG approach, we have also performed quantum Monte Carlo simulations to obtain the magnetization, the susceptibility, and the correlation length of the two-dimensional spin-$1/2$ quantum $XY$ model with coupling $J$ in a regime where its quantum critical behavior is controlled by the dilute Bose gas quantum critical point. We find that our analytical results describe the Monte Carlo data for $\mu \leq 0$ rather accurately up to relatively high temperatures $T \lesssim 0.1 J$. Comment: 18 pages, 13 figures |
| Databáze: | OpenAIRE |
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