Dynamical Critical Scaling of Long-Range Interacting Quantum Magnets
Year: 2018
Authors: Defenu N., Enss T., Kastner M., Morigi G.
Autors Affiliation: Heidelberg Univ, Inst Theoret Phys, D-69120 Heidelberg, Germany; Univ Stellenbosch, Inst Theoret Phys, Dept Phys, ZA-7600 Stellenbosch, South Africa; Natl Inst Theoret Phys NITheP, ZA-7600 Stellenbosch, South Africa; Univ Saarland, Theoret Phys, D-66123 Saarbrucken, Germany.
Abstract: Slow quenches of the magnetic field across the paramagnetic-ferromagnetic phase transition of spin systems produce heat. In systems with short-range interactions the heat exhibits universal power-law scaling as a function of the quench rate, known as Kibble-Zurek scaling. In this work we analyze slow quenches of the magnetic field in the Lipkin-Meshkov-Glick (LMG) model, which describes fully connected quantum spins. We analytically determine the quantum contribution to the residual heat as a function of the quench rate delta by means of a Holstein-Primakoff expansion about the mean-field value. Unlike in the case of short-range interactions, scaling laws in the LMG model are only found for a ramp starting or ending at the critical point. If instead the ramp is symmetric, as in the typical Kibble-Zurek scenario, then the number of excitations exhibits a crossover behavior as a function of delta and tends to a constant in the thermodynamic limit. Previous, and seemingly contradictory, theoretical studies are identified as specific limits of this dynamics. Our results can be tested on several experimental platforms, including quantum gases and trapped ions.
Journal/Review: PHYSICAL REVIEW LETTERS
Volume: 121 (24) Pages from: 240403-1 to: 240403-6
More Information: N.D. acknowledges fruitful discussions with G. Gori, G. M. Graaf, S. Ruffo, and A. Trombettoni. G. M. is grateful to L. Hruby, S. Jager, H. Ritsch, and V. Torggler for stimulating discussions. Financial support by the DFG Collaborative Research Centre SFB 1225 ISOQUANT, by the DFG DACH project Quantum crystals of matter and light, by the German Ministry of Education and Research (BMBF) via the Quantera project NAQUAS, and by the Competitive Programme for Rated Researchers of the NRF South Africa is acknowledged. Project NAQUAS has received funding from the QuantERA ERA-NET Cofund in Quantum Technologies implemented within the European Union’s Horizon 2020 Programme.KeyWords: Dependent Harmonic-oscillator; Phase-transition; Cosmological Experiments; Symmetry-breaking; Propagation; Coherence; Particle; Systems; FieldDOI: 10.1103/PhysRevLett.121.240403ImpactFactor: 9.227Citations: 51data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2024-11-10References taken from IsiWeb of Knowledge: (subscribers only)
