Efficient Quantum Cooling Algorithm for Fermionic Systems

• URL: http://arxiv.org/abs/2403.14506v1
• Date: Thu, 21 Mar 2024 15:59:32 GMT
• Title: Efficient Quantum Cooling Algorithm for Fermionic Systems
• Authors: Lucas Marti, Refik Mansuroglu, Michael J. Hartmann,
• Abstract summary: We present a cooling algorithm for ground state preparation of fermionic Hamiltonians. We derive suitable interaction Hamiltonians that originate from operators of the free theory. We propose a spectroscopic scan to find the relevant eigenenergies of the system.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: We present a cooling algorithm for ground state preparation of fermionic Hamiltonians. Our algorithm makes use of the Hamiltonian simulation of the considered system coupled to an ancillary fridge, which is regularly reset to its known ground state. We derive suitable interaction Hamiltonians that originate from ladder operators of the free theory and initiate resonant gaps between system and fridge. We further propose a spectroscopic scan to find the relevant eigenenergies of the system using energy measurements on the fridge. With these insights, we design a ground state cooling algorithm for fermionic systems that is efficient, i.e. its runtime is polynomial in the system size, as long as the initial state is prepared in a low energy sector of polynomial size. We achieve the latter via a fast, quasi-adiabatic sweep from a parameter regime whose ground state can be easily prepared. We generalize the algorithm to prepare thermal states and demonstrate our findings on the Fermi-Hubbard model.

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