Circuit complexity as a novel probe of quantum entanglement: A study with black hole gas in arbitrary dimensions
Kiran Adhikari (Institute for Theoretical Particle Physics and Cosmology(TTK), RWTH Aachen University, D-52056 Aachen, Germany); Sayantan Choudhury (National Institute of Science Education and Research, Jatni, Bhubaneswar, Odisha—752050, India, Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai—400085, India); Satyaki Chowdhury (National Institute of Science Education and Research, Jatni, Bhubaneswar, Odisha—752050, India, Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai—400085, India); K. Shirish (Visvesvaraya National Institute of Technology, Nagpur, Maharashtra 440010, India); Abinash Swain (Department of Physics, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar- 382355, India)
In this article, we investigate the quantum circuit complexity and entanglement entropy in the recently studied black hole gas framework using the two-mode squeezed states formalism written in arbitrary dimensional spatially flat cosmological Friedmann-Lemaître-Robertson-Walker background space-time. We compute the various complexity measures and study the evolution of these complexities by following two different prescriptions viz the covariant matrix method and Nielsen’s method. Independently, using the two-mode squeezed states formalism we also compute the Rényi and von-Neumann entanglement entropy, which show an inherent connection between the entanglement entropy and quantum circuit complexity. We study the behavior of the complexity measures and entanglement entropy separately for three different spatial dimensions and observe various significant different features in three spatial dimensions on the evolution of these quantities with respect to the scale factor. Furthermore, we also study the underlying behavior of the equilibrium temperature with two of the most essential quantities i.e., rate of change of complexity with scale factor and the entanglement entropy. We observe that irrespective of the spatial dimension, the equilibrium temperature depends quartically on entanglement entropy.
