SciPost Submission Page
Experimental protocol for observing single quantum many-body scars with transmon qubits
by Peter Græns Larsen, Anne E. B. Nielsen, André Eckardt, Francesco Petiziol
Submission summary
| Authors (as registered SciPost users): | Francesco Petiziol |
| Submission information | |
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| Preprint Link: | https://arxiv.org/abs/2410.14613v2 (pdf) |
| Date submitted: | Aug. 12, 2025, 9:38 a.m. |
| Submitted by: | Francesco Petiziol |
| Submitted to: | SciPost Physics |
| Ontological classification | |
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| Academic field: | Physics |
| Specialties: |
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| Approach: | Theoretical |
Abstract
Quantum many-body scars are energy eigenstates which fail to reproduce thermal expectation values of local observables, in systems where the rest of the many-body spectrum fulfils eigenstate thermalization. Experimental observation of quantum many-body scars has so far been limited to models with multiple scar states evenly spaced in energy. It is thus an interesting question whether even single isolated scars, which theoretically embody the weakest possibile violation of eigenstate thermalization and may be thought to have no detectable impact in experiments, can leave a trace in measurable quantities. Moreover, single scars offer an interesting scenario for exploring the connection between quantum many-body scars and the original notion of scarring in quantum dynamical systems theory. Here we propose protocols to observe single scars in architectures of fixed-frequency, fixed-coupling superconducting qubits. We first adapt known models possessing the desired features into a form particularly suited for the experimental platform. We develop protocols for the implementation of these models, through trotterized sequences of two-qubit cross-resonance interactions, and verify the existence of the approximate scar state in the stroboscopic effective Hamiltonian. Since a single scar cannot be detected from coherent revivals in the dynamics, differently from towers of scar states, we propose and numerically investigate alternative and experimentally-accessible signatures. These include the dynamical response of the scar to local state deformations, to controlled noise, and to the resolution of the Lie-Suzuki-Trotter digitization.
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
thank you for your evaluation of our manuscript "Experimental protocol for observing single quantum many-body scars with transmon qubits" and for returning to us the Referees' reports.
We thank both Referees for their time and constructive comments, which allowed us to highlight even more the relevance of our work and to strengthen the presentation.
Both Referees gave positive feedback and recommended minor revisions, which regard a more detailed introduction to the research field, a more detailed discussion of the motivation behind our study in relation to the broader context of quantum many-body scars, and the interest of studying single scars. We addressed these aspects in detail by largely revising and expanding the introduction, which now includes a broader perspective on the field, a detailed discussion about the interest in isolated scars and about their connection to both other scarring phenomena in quantum many-body systems and the original notion of scarring in quantum chaos. Regarding the latter, we want to thank Referee 2 for pointing out this interesting connection to us.
Given the positive recommendation by both referees and the revision which, we feel, further improved the manuscript, we hope you will now find our resubmission suitable for publication in SciPost Phys.
Sincerely,
Francesco Petiziol, on behalf of all authors