Approximating quantum thermodynamic properties using DFT

Abstract

The fabrication, utilisation, and efficiency of quantum technologies rely on a good understanding of quantum thermodynamic properties. Many-body systems are often used as hardware for these quantum devices, but interactions between particles make the complexity of related calculations grow exponentially with the system size. Here we explore and systematically compare `simple' and `hybrid' approximations to the average work and entropy variation built on static density functional theory concepts. These approximations are computationally cheap and could be applied to large systems. We exemplify them considering driven one-dimensional Hubbard chains and show that, for `simple' approximations and low to medium temperatures, it pays to consider a good Kohn-Sham Hamiltonian to approximate the driving Hamiltonian. Our results confirm that a `hybrid' approach, requiring a very good approximation of the initial and, for the entropy, final states of the system, provides great improvements. This approach should be particularly efficient when many-body effects are not increased by the driving Hamiltonian.

References in corpus (16)

• QuTiP 2: A Python framework for the dynamics of open quantum systems
• Real time evolution using the density matrix renormalization group
• The Statistics of the Work Done on a Quantum Critical System by Quenching a Control Parameter
• Two Fermions in a double well: Exploring a fundamental building block of the Hubbard model
• Generalized Clausius inequality for nonequilibrium quantum processes
• Assessing the non-equilibrium thermodynamics in a quenched quantum many-body system via single projective measurements
• Kohn-Sham calculations with the exact functional
• Entanglement entropy and entanglement witnesses in models of strongly interacting low-dimensional fermions
• The Hubbard model as an approximation to the entanglement in nanostructures
• Spectral properties of a partially spin-polarized one-dimensional Hubbard/Luttinger superfluid
• Feasibility of approximating spatial and local entanglement in long-range interacting systems using the extended Hubbard model
• Quantum Hertz entropy increase in a quenched spin chain
• Uniqueness of density-to-potential mapping for fermionic lattice systems
• Experimental realization of fragmented models in tilted Fermi-Hubbard chains
• Towards overcoming the entanglement barrier when simulating long-time evolution
• Symmetries and boundary conditions with a twist