Ultrafast Entanglement Dynamics in Monitored Quantum Circuits
- URL: http://arxiv.org/abs/2212.10634v1
- Date: Tue, 20 Dec 2022 20:22:39 GMT
- Title: Ultrafast Entanglement Dynamics in Monitored Quantum Circuits
- Authors: Shengqi Sang, Zhi Li, Timothy H. Hsieh and Beni Yoshida
- Abstract summary: We study the non-equilibrium dynamics of weakly monitored quantum circuits.
We find entanglement dynamics in monitored circuits is indeed "faster" than that of unitary ones.
- Score: 2.8876257574732604
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Projective measurement, a basic operation in quantum mechanics, can induce
seemingly nonlocal effects. In this work, we analyze such effects in many-body
systems by studying the non-equilibrium dynamics of weakly monitored quantum
circuits, focusing on entanglement generation and information spreading. We
find that, due to measurements, the entanglement dynamics in monitored circuits
is indeed "faster" than that of unitary ones in several ways. Specifically, we
find that a pair of well-separated regions can become entangled in a time scale
$\ell^{2/3}$, sub-linear in their distance $\ell$. For the case of Clifford
monitored circuits, this originates from super-ballistically growing stabilizer
generators of the evolving state. In addition, we find initially local
information can spread super-ballistically as $t^{3/2}$. Furthermore, by
viewing the dynamics as a dynamical encoding process, we show that the
super-ballistic growing length scale relates to an encoding time that is
sublinear in system size. To quantify the information dynamics, we develop a
formalism generalizing operator spreading to non-unitary dynamics, which is of
independent interest.
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