Spontaneous strong symmetry breaking in open systems: Purification perspective

P Sala, S Gopalakrishnan, M Oshikawa, Y You - Physical Review B, 2024 - APS
We explore the effect of decoherence on many-body mixed states from a purification
perspective. Here, quantum channels map to unitary transformations acting on a purified …

Disentangling transitions in topological order induced by boundary decoherence

TC Lu - Physical Review B, 2024 - APS
We study the entanglement structure of topological orders subject to decoherence on the
bipartition boundary. Focusing on the toric codes in d space dimensions for d= 2, 3, 4, we …

Locally purified density operators for symmetry-protected topological phases in mixed states

Y Guo, JH Zhang, HR Zhang, S Yang, Z Bi - arXiv preprint arXiv …, 2024 - arxiv.org
We propose a tensor network approach known as the locally purified density operator
(LPDO) to investigate the classification and characterization of symmetry-protected …

[PDF][PDF] Intrinsic mixed-state topological order without quantum memory

Z Wang, Z Wu, Z Wang - arXiv preprint arXiv:2307.13758, 2023 - researchgate.net
Decoherence is a major obstacle to the preparation of topological order in noisy
intermediate-scale quantum devices. Here, we show that decoherence can also give rise to …

Spontaneous symmetry breaking in open quantum systems: strong, weak, and strong-to-weak

D Gu, Z Wang, Z Wang - arXiv preprint arXiv:2406.19381, 2024 - arxiv.org
Depending on the coupling to the environment, symmetries of open quantum systems
manifest in two distinct forms, the strong and the weak. We study the spontaneous symmetry …

Decoherence and wavefunction deformation of non-Abelian topological order

P Sala, J Alicea, R Verresen - arXiv preprint arXiv:2409.12948, 2024 - arxiv.org
The effect of decoherence on topological order (TO) has been most deeply understood for
the toric code, the paragon of Abelian TOs. We show that certain non-Abelian TOs can be …

Intrinsic symmetry-protected topological mixed state from modulated symmetries and hierarchical structure of boundary anomaly

Y You, M Oshikawa - Physical Review B, 2024 - APS
We introduce a class of intrinsic symmetry-protected topological mixed state (mSPT) in open
quantum systems that feature modulated symmetries, such as dipole and subsystem …

Stability of mixed-state quantum phases via finite Markov length

S Sang, TH Hsieh - arXiv preprint arXiv:2404.07251, 2024 - arxiv.org
For quantum phases of Hamiltonian ground states, the energy gap plays a central role in
ensuring the stability of the phase as long as the gap remains finite. We propose Markov …

Strong-to-weak spontaneous breaking of 1-form symmetry and intrinsically mixed topological order

C Zhang, Y Xu, JH Zhang, C Xu, Z Bi… - arXiv preprint arXiv …, 2024 - arxiv.org
Topological orders in 2+ 1d are spontaneous symmetry-breaking (SSB) phases of 1-form
symmetries in pure states. The notion of symmetry is further enriched in the context of mixed …

Strong-to-weak spontaneous symmetry breaking in mixed quantum states

LA Lessa, R Ma, JH Zhang, Z Bi, M Cheng… - arXiv preprint arXiv …, 2024 - arxiv.org
Symmetry in mixed quantum states can manifest in two distinct forms: strong symmetry,
where each individual pure state in the quantum ensemble is symmetric with the same …