Nature of the nonequilibrium phase transition in the non-Markovian driven Dicke model
Journal Article
·
· Physical Review A
- Joint Quantum Institute, College Park, MD (United States); National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); Univ. of Maryland, College Park, MD (United States); OSTI
- Joint Quantum Institute, College Park, MD (United States); National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); Univ. of Maryland, College Park, MD (United States); Joint Center for Quantum Information and Computer Science, College Park, MD (United States)
- Michigan State Univ., East Lansing, MI (United States)
The Dicke model famously exhibits a phase transition to a superradiant phase with a macroscopic population of photons and is realized in multiple settings in open quantum systems. In this paper, we study a variant of the Dicke model where the cavity mode is lossy due to the coupling to a Markovian environment while the atomic mode is coupled to a colored bath. We analytically investigate this model by inspecting its low-frequency behavior via the Schwinger-Keldysh field theory and carefully examine the nature of the corresponding superradiant phase transition. Integrating out the fast modes, we can identify a simple effective theory allowing us to derive analytical expressions for various critical exponents including the dynamical exponent. We find excellent agreement with previous numerical results when the non-Markovian bath is at zero temperature; however, contrary to these studies, our low-frequency approach reveals that the same exponents govern the critical behavior when the colored bath is at finite temperature unless the chemical potential is zero. Furthermore, we show that the superradiant phase transition is classical in nature, while it is genuinely nonequilibrium. In this work, we derive a fractional Langevin equation and conjecture the associated fractional Fokker-Planck equation that captures the system's long-time memory as well as its nonequilibrium behavior. Finally, we consider finite-size effects at the phase transition and identify the finite-size scaling exponents, unlocking a rich behavior in both statics and dynamics of the photonic and atomic observables.
- Research Organization:
- Duke Univ., Durham, NC (United States); Duke University, Durham, NC (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); US Air Force Office of Scientific Research (AFOSR); USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0019449
- OSTI ID:
- 1803839
- Alternate ID(s):
- OSTI ID: 2280949
- Journal Information:
- Physical Review A, Journal Name: Physical Review A Journal Issue: 3 Vol. 102; ISSN 2469-9926
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
No singularities in observables at the phase transition in the Dicke model
Journal Article
·
Sun May 15 00:00:00 EDT 2011
· Physical Review. A
·
OSTI ID:21546680