Isentropic Curves at Magnetic Phase Transitions
arXiv:1009.0791 · doi:10.1103/PhysRevB.83.045108
Abstract
Experiments on cold atom systems in which a lattice potential is ramped up on a confined cloud have raised intriguing questions about how the temperature varies along isentropic curves, and how these curves intersect features in the phase diagram. In this paper, we study the isentropic curves of two models of magnetic phase transitions- the classical Blume-Capel Model (BCM) and the Fermi Hubbard Model (FHM). Both Mean Field Theory (MFT) and Monte Carlo (MC) methods are used. The isentropic curves of the BCM generally run parallel to the phase boundary in the Ising regime of low vacancy density, but intersect the phase boundary when the magnetic transition is mainly driven by a proliferation of vacancies. Adiabatic heating occurs in moving away from the phase boundary. The isentropes of the half-filled FHM have a relatively simple structure, running parallel to the temperature axis in the paramagnetic phase, and then curving upwards as the antiferromagnetic transition occurs. However, in the doped case, where two magnetic phase boundaries are crossed, the isentrope topology is considerably more complex.
References in corpus (11)
- Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
- Ultracold atomic gases in optical lattices: mimicking condensed matter physics and beyond
- Direct Observation of the Superfluid Phase Transition in Ultracold Fermi Gases
- Spontaneously modulated spin textures in a dipolar spinor Bose-Einstein condensate
- Quantitative Determination of Temperature in the Approach to Magnetic Order of Ultracold Fermions in an Optical Lattice
- Condensate fraction in a 2D Bose gas measured across the Mott-insulator transition
- Quantum Simulation and Phase Diagram of the Transverse Field Ising Model with Three Atomic Spins
- Interaction-Induced Adiabatic Cooling for Antiferromagnetism in Optical Lattices
- Phases of a 2D Bose Gas in an Optical Lattice
- Monte Carlo studies of extensions of the Blume-Emery-Griffiths model
- First order phase transitions in classical lattice gas spin models