Abstract
Free-Fermionic Topological Quantum Sensors
Phys. Rev. Lett. 129, 090503 (2022) Saubhik Sarkar, Chiranjib Mukhopadhyay, Abhijeet Alase and Abolfazl Bayat. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.129.090503
Second order quantum phase transitions, with well-known features such as long-range entanglement, symmetry breaking, and gap closing, exhibit quantum enhancement for sensing at criticality. However, it is unclear which of these features are responsible for this enhancement.
To address this issue, we investigate phase transitions in free-fermionic topological systems that exhibit neither symmetry-breaking nor long-range entanglement. We analytically demonstrate that quantum enhanced sensing is possible using topological edge states near the phase boundary.
Remarkably, such enhancement also endures for ground states of such models that are accessible in solid state experiments. We illustrate the results with 1D Su-Schrieffer-Heeger chain and a 2D Chern insulator which are both experimentally accessible. While neither symmetry-breaking nor long-range entanglement are essential, gap closing remains as the major candidate for the ultimate source of quantum enhanced sensing.
In addition, we also provide a fixed and simple measurement strategy that achieves near-optimal precision for sensing using generic edge states irrespective of the parameter value. This paves the way for development of topological quantum sensors which are expected to also be robust against local perturbations.
About the qGAP meeting series
Welcome to qGAP, our seminar series on Quantum Physics and Quantum Technology.
The series of seminars/lectures are meant to cover broadly activities at UiO and elsewhere related to quantum physics and technologies, mainly from a theoretical perspective, though we also welcome experimental talks.
We aim at having regular seminars, discussions of recent articles, presentations by master and PhD students and more. We aim for this series to be a combination of research talks and journal clubs.
Educational topics are also most welcome.
Please feel free to suggest speakers, yourself included!
Get in touch with Gunnar Lange to suggest a speaker or if you would like to be included in the mailing list.
All are welcome!
Upcoming:
14. Februar - Kishore Thapliyal (UiO Fysikk)
21. Februar - Viktor Svensson (UiO Fysikk)
27. Februar - Sølve Selstø (OsloMet)
4. April - Alexander Müller-Hermes (UiO Matematikk)