Entanglement Steering in Adaptive Circuits with Feedback
- URL: http://arxiv.org/abs/2211.05162v4
- Date: Sat, 15 Jul 2023 04:13:47 GMT
- Title: Entanglement Steering in Adaptive Circuits with Feedback
- Authors: Vikram Ravindranath, Yiqiu Han, Zhi-Cheng Yang, Xiao Chen
- Abstract summary: We introduce a class of adaptive random circuit models with feedback that exhibit transitions in both settings.
We demonstrate that the former transition belongs to the parity-conserving universality class by an explicit mapping to a classical branching-annihilating random walk process.
- Score: 6.5014847595384495
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: The intensely studied measurement-induced entanglement phase transition has
become a hallmark of non-unitary quantum many-body dynamics. Usually, such a
transition only shows up at the level of each individual quantum trajectory,
and is absent for the density matrix averaged over measurement outcomes. In
this work, we introduce a class of adaptive random circuit models with feedback
that exhibit transitions in both settings. After each measurement, a unitary
operation is either applied or not depending on the measurement outcome, which
steers the averaged density matrix towards a unique state above a certain
measurement threshold. Interestingly, the transition for the density matrix and
the entanglement transition in the individual quantum trajectory in general
happen at \textit{different} critical measurement rates. We demonstrate that
the former transition belongs to the parity-conserving universality class by an
explicit mapping to a classical branching-annihilating random walk process.
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