SciPost Submission Page
Non-unitarity maximizing unraveling of open quantum dynamics
by Ruben Daraban, Fabrizio Salas-Ramírez, Johannes Schachenmayer
Submission summary
| Authors (as registered SciPost users): | Ruben Daraban · Johannes Schachenmayer |
| Submission information | |
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| Preprint Link: | https://arxiv.org/abs/2410.11690v2 (pdf) |
| Date accepted: | Jan. 20, 2025 |
| Date submitted: | Jan. 13, 2025, 10:58 a.m. |
| Submitted by: | Ruben Daraban |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Computational |
Abstract
The dynamics of many-body quantum states in open systems is commonly numerically simulated by unraveling the density matrix into pure-state trajectories. In this work, we introduce a new unraveling strategy that can adaptively minimize the averaged entanglement in the trajectory states. This enables a more efficient classical representation of trajectories using matrix product decompositions. Our new approach is denoted non-unitarity maximizing unraveling (NUMU). It relies on the idea that adaptively maximizing the averaged non-unitarity of a set of Kraus operators leads to a more efficient trajectory entanglement destruction. Compared to other adaptive entanglement lowering algorithms, NUMU is computationally inexpensive. We demonstrate its utility in large-scale simulations with random quantum circuits. NUMU lowers runtimes in practical calculations, and it also provides new insight on the question of classical simulability of quantum dynamics. We show that for the quantum circuits considered here, unraveling methods are much less efficient than full matrix product density operator simulations, hinting to a still large potential for finding more advanced adaptive unraveling schemes.
Author indications on fulfilling journal expectations
- Provide a novel and synergetic link between different research areas.
- Open a new pathway in an existing or a new research direction, with clear potential for multi-pronged follow-up work
- Detail a groundbreaking theoretical/experimental/computational discovery
- Present a breakthrough on a previously-identified and long-standing research stumbling block
Author comments upon resubmission
In response to their comments and remarks, we have modified the manuscript as described in detail below.
Changes include: addressing the feedback provided by the reviewers, fixing typographical errors, and adding references.
We believe that the updates helped to enhance the clarity and completeness of the manuscript.
List of changes
- Improved Figure 1 and revised its caption in response to a question of Referee 2.
- Converted an inline equation into a numbered equation (Eq. (19), page 9).
- Removed a superfluous 1/2 factor in Eqs. (23) and (24), with no impact on later equations.
- Added a reference in the last paragraph of page 10, suggested by a Referee 2 (reference [53] in v2).
- Corrected a constant error in Eq. (32) (revised from a factor of 2 to the trace of the identity).
- Fixed a caption error in Figure 4, noted by Referee 2.
- Reformulated the last paragraph of Section 4.2, addressing a comment of Referee 1.
- Added a clarifying sentence to the first paragraph of Section 5.
- Included a pseudocode implementation of NUMU in Appendix F, in response to a comment of Referee 1.
Published as SciPost Phys. 18, 048 (2025)