Universität zu Köln

Klocke, Kai and Buchhold, Michael ORCID: 0000-0001-5194-9388 (2022). Topological order and entanglement dynamics in the measurement-only XZZX quantum code. Phys. Rev. B, 106 (10). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2469-9969

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Abstract

We examine the dynamics of a (1 + 1)-dimensional measurement-only circuit defined by the stabilizers of the [[5,1,3]] quantum error correcting code interrupted by single-qubit Pauli measurements. The code corrects arbitrary single-qubit errors and it stabilizes an area law entangled state with a D-2 = Z(2) x Z(2) symmetry protected topological (SPT) order, as well as a symmetry breaking (SB) order from a twofold bulk degeneracy. The Pauli measurements break the topological order and induce a phase transition into a trivial area law phase. Allowing more than one type of Pauli measurement increases the measurement-induced frustration and the SPT and SB order can be broken either simultaneously or separately at nonzero measurement rate. This yields a rich phase diagram and unanticipated critical behavior at the phase transitions. Although the correlation length exponent nu = 4/3 and the dynamical critical exponent z = 1 are consistent with bond percolation, the prefactor of the logarithmic entanglement growth may take noninteger multiples of the percolation value. Remarkably, we identify a robust transient scaling regime for the purification dynamics of L qubits. It reveals a modified dynamical critical exponent z* not equal z, which is observable up to times t similar to L-z* and is reminiscent of the relaxation of critical systems into a prethermal state.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Klocke, Kai UNSPECIFIED UNSPECIFIED UNSPECIFIED Buchhold, Michael UNSPECIFIED orcid.org/0000-0001-5194-9388 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-671147
DOI:	10.1103/PhysRevB.106.104307
Journal or Publication Title:	Phys. Rev. B
Volume:	106
Number:	10
Date:	2022
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	2469-9969
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language BEHAVIOR Multiple languages Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/67114