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arXiv · 2204.01791

Boiling Quantum Vacuum: Thermal Subsystems from Ground-State Entanglement

Ali G. Moghaddam·Kim Pöyhönen·Teemu Ojanen
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Abstract

In certain special circumstances, such as in the vicinity of a black hole or in a uniformly accelerating frame, vacuum fluctuations appear to give rise to a finite-temperature environment. This effect, currently without experimental confirmation, can be interpreted as a manifestation of quantum entanglement after tracing out vacuum modes in an unobserved region. In this work, we identify a class of experimentally accessible quantum systems where thermal density matrices emerge from vacuum entanglement. We show that reduced density matrices of lower-dimensional subsystems embedded in $D$-dimensional gapped Dirac fermion vacuum, either on a lattice or continuum, have a thermal form with respect to a lower-dimensional Dirac Hamiltonian. Strikingly, we show that vacuum entanglement can even conspire to make a subsystem of a gapped system at zero temperature appear as a hot gapless system. We propose concrete experiments in cold atom quantum simulators to observe the vacuum entanglement induced thermal states.

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Ali G. Moghaddam, Kim Pöyhönen, Teemu Ojanen. 2022-04-04. Boiling Quantum Vacuum: Thermal Subsystems from Ground-State Entanglement. https://doi.org/10.1103/prxquantum.3.030335

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