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Café com Física |
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09/11
16:00 hrs Sala F-147 Irene D’Amico Department of Physics University of York Density Functional Theory Inspired Approaches to Quantum Thermodynamics Hardware for quantum devices often comprises many-body systems composed by a relatively small number of quantum degrees of freedom. Understanding thermodynamic properties of these systems is crucial as they could limit applications, and/or help the fabrication and running of efficient quantum devices. Relevant dynamics are often at finite temperature, strongly out-of-equilibrium and including non-negligible many-body interactions: the theorist nightmare. In particular, interactions between particles make the complexity of related calculations grow exponentially with the system size. Here [1,2,3,4] we explore and compare approximations to the estimate of the average work built on static density functional theory concepts. These approximations are computationally cheap, could be applied to large systems, and to the calculation of other properties. We demonstrate them by considering a driven one-dimensional Hubbard chains which undergoes transitions to a Mott insulator and to a band-insulator transitions at different temperatures. For ‘simple’ [3] approximations and low to medium temperatures, it pays to consider a good estimate of the Kohn–Sham Hamiltonian to approximate the driving Hamiltonian [4]. Our results confirm that a ‘hybrid’ approach [3], which also requires a very good approximation of the initial state of the system, provides great improvements [3,4]. This approach should be particularly efficient when many-body effects are not increased by the driving Hamiltonian. References: [1] M. Herrera, R. Serra, and I. D’Amico, Sci. Reports 7 4655 (2017) [2] M. Herrera, K. Zawadzki and I. D’Amico, Eur. Phys. J. B 91, 248 (2018) [3] A. H. Skelt, K. Zawadzki and I. D’Amico, J. Phys. A: Math. Theor. 52, 485304 (2019) [4] K. Zawadzki, A. H. Skelt and I. D’Amico, J. Phys: Condens. Matter 34, 274002 (2022) 
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