Finite-time teleportation phase transition in random quantum circuits

Fuente: arXiv
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Main Authors: Bao, Yimu, Block, Maxwell, Altman, Ehud
Format: Preprint
Published: 2021
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author Bao, Yimu
Block, Maxwell
Altman, Ehud
author_facet Bao, Yimu
Block, Maxwell
Altman, Ehud
contents How long does it take to entangle two distant qubits in a quantum circuit evolved by generic unitary dynamics? We show that if the time evolution is followed by measurements of all but two infinitely separated test qubits, then the entanglement between them can undergo a phase transition and become nonzero at a finite critical time $t_c$. The fidelity of teleporting a quantum state from an input qubit to an infinitely distant output qubit shows the same critical onset. Specifically, these finite-time transitions occur in short-range interacting two-dimensional random unitary circuits and in sufficiently long-range interacting one-dimensional circuits. The phase transition is understood by mapping the random continuous-time evolution to a finite-temperature thermal state of an effective spin Hamiltonian, where the inverse temperature equals the evolution time in the circuit. In this framework, the entanglement between two distant qubits at times $t>t_c$ corresponds to the emergence of long-range ferromagnetic spin correlations below the critical temperature. We verify these predictions using numerical simulation of Clifford circuits and propose potential realizations in existing platforms for quantum simulation.
format Preprint
id arxiv_https___arxiv_org_abs_2110_06963
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Finite-time teleportation phase transition in random quantum circuits
Bao, Yimu
Block, Maxwell
Altman, Ehud
Quantum Physics
Statistical Mechanics
How long does it take to entangle two distant qubits in a quantum circuit evolved by generic unitary dynamics? We show that if the time evolution is followed by measurements of all but two infinitely separated test qubits, then the entanglement between them can undergo a phase transition and become nonzero at a finite critical time $t_c$. The fidelity of teleporting a quantum state from an input qubit to an infinitely distant output qubit shows the same critical onset. Specifically, these finite-time transitions occur in short-range interacting two-dimensional random unitary circuits and in sufficiently long-range interacting one-dimensional circuits. The phase transition is understood by mapping the random continuous-time evolution to a finite-temperature thermal state of an effective spin Hamiltonian, where the inverse temperature equals the evolution time in the circuit. In this framework, the entanglement between two distant qubits at times $t>t_c$ corresponds to the emergence of long-range ferromagnetic spin correlations below the critical temperature. We verify these predictions using numerical simulation of Clifford circuits and propose potential realizations in existing platforms for quantum simulation.
title Finite-time teleportation phase transition in random quantum circuits
topic Quantum Physics
Statistical Mechanics
url https://arxiv.org/abs/2110.06963