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arXiv · 2311.10566

Hamiltonian Forging of a Thermofield Double

Daniel Faílde·Juan Santos-Suárez·David A. Herrera-Martí·Javier Mas
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Abstract

We address the variational preparation of the Thermofield Double as the ground state of a suitably engineered Hamiltonian acting on the doubled Hilbert space. Through the use of the Entanglement Forging ansatz, we propose a solution that involves only circuits of width $N$. We illustrate the method with generic fermionic Hamiltonians. The free fermion case can be solved in closed form, and yields a warm start state for the variational circuits whenever interactions are present. As an important side product, this method returns the complete energy spectrum and eigenbasis of the system.

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Daniel Faílde, Juan Santos-Suárez, David A. Herrera-Martí, Javier Mas. 2023-11-17. Hamiltonian Forging of a Thermofield Double. https://doi.org/10.1103/physreva.111.012432

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