- Letter
- Open Access
Constraining work fluctuations of non-Hermitian dynamics across the exceptional point of a superconducting qubit
Phys. Rev. Research 6, L022013 – Published 16 April, 2024
DOI: https://doi.org/10.1103/PhysRevResearch.6.L022013
Abstract
Thermodynamics constrains changes to the energy of a system, both deliberate and random, via its first and second laws. When the system is not in equilibrium, fluctuation theorems such as the Jarzynski equality further restrict the distributions of deliberate work done. Such fluctuation theorems have been experimentally verified in small, nonequilibrium quantum systems undergoing unitary or decohering dynamics. Yet, their validity in systems governed by a non-Hermitian Hamiltonian has long been contentious due to the false premise of the Hamiltonian's dual and equivalent roles in dynamics and energetics. Here we show that work fluctuations in a non-Hermitian qubit obey the Jarzynski equality even if its Hamiltonian has complex or purely imaginary eigenvalues. With postselection on a dissipative superconducting circuit undergoing a cyclic parameter sweep, we experimentally quantify the work distribution using projective energy measurements and show that the fate of the Jarzynski equality is determined by the parity-time symmetry of, and the energetics that result from, the corresponding non-Hermitian, Floquet Hamiltonian. By distinguishing the energetics from non-Hermitian dynamics, our results provide the recipe for investigating the nonequilibrium quantum thermodynamics of such open systems.
Physics Subject Headings (PhySH)
Article Text
References (65)
- R. Alicki, The quantum open system as a model of the heat engine, J. Phys. A: Math. Gen. 12, L103 (1979).
- R. Kosloff, A quantum mechanical open system as a model of a heat engine, J. Chem. Phys. 80, 1625 (1984).
- H. Spohn and J. L. Lebowitz, Irreversible thermodynamics for quantum systems weakly coupled to thermal reservoirs, in Advances in Chemical Physics (John Wiley & Sons, Inc., 2007), pp. 109–142.
- J. M. Horowitz, Quantum-trajectory approach to the stochastic thermodynamics of a forced harmonic oscillator, Phys. Rev. E 85, 031110 (2012).
- J. J. Alonso, E. Lutz, and A. Romito, Thermodynamics of weakly measured quantum systems, Phys. Rev. Lett. 116, 080403 (2016).
- C. Elouard, D. A. Herrera-Martí, M. Clusel, and A. Auffèves, The role of quantum measurement in stochastic thermodynamics, npj Quantum Inf 3, 9 (2017).
- P. M. Harrington, E. J. Mueller, and K. W. Murch, Engineered dissipation for quantum information science, Nat. Rev. Phys. 4, 660 (2022).
- D. A. Lidar, Lecture notes on the theory of open quantum systems, arXiv:1902.00967.
- M. Naghiloo, D. Tan, P. M. Harrington, J. J. Alonso, E. Lutz, A. Romito, and K. W. Murch, Heat and work along individual trajectories of a quantum bit, Phys. Rev. Lett. 124, 110604 (2020).
- C. Jarzynski, Nonequilibrium equality for free energy differences, Phys. Rev. Lett. 78, 2690 (1997).
- J. Kurchan, Fluctuation theorem for stochastic dynamics, J. Phys. A: Math. Gen. 31, 3719 (1998).
- G. E. Crooks, Entropy production fluctuation theorem and the nonequilibrium work relation for free energy differences, Phys. Rev. E 60, 2721 (1999).
- H. Tasaki, Jarzynski relations for quantum systems and some applications, arXiv:cond-mat/0009244.
- G. Huber, F. Schmidt-Kaler, S. Deffner, and E. Lutz, Employing trapped cold ions to verify the quantum Jarzynski equality, Phys. Rev. Lett. 101, 070403 (2008).
- J. Kurchan, A quantum fluctuation theorem, arXiv:cond-mat/0007360.
- S. Mukamel, Quantum extension of the Jarzynski relation: Analogy with stochastic dephasing, Phys. Rev. Lett. 90, 170604 (2003).
- T. Albash, D. A. Lidar, M. Marvian, and P. Zanardi, Fluctuation theorems for quantum processes, Phys. Rev. E 88, 032146 (2013).
- A. E. Rastegin, Non-equilibrium equalities with unital quantum channels, J. Stat. Mech.: Theory Exp. (2013) P06016.
- T. B. Batalhão, A. M. Souza, L. Mazzola, R. Auccaise, R. S. Sarthour, I. S. Oliveira, J. Goold, G. D. Chiara, M. Paternostro, and R. M. Serra, Experimental reconstruction of work distribution and study of fluctuation relations in a closed quantum system, Phys. Rev. Lett. 113, 140601 (2014).
- S. An, J.-N. Zhang, M. Um, D. Lv, Y. Lu, J. Zhang, Z.-Q. Yin, H. T. Quan, and K. Kim, Experimental test of the quantum Jarzynski equality with a trapped-ion system, Nat. Phys. 11, 193 (2015).
- F. Cerisola, Y. Margalit, S. Machluf, A. J. Roncaglia, J. P. Paz, and R. Folman, Using a quantum work meter to test non-equilibrium fluctuation theorems, Nat. Commun. 8, 1241 (2017).
- T. P. Xiong, L. L. Yan, F. Zhou, K. Rehan, D. F. Liang, L. Chen, W. L. Yang, Z. H. Ma, M. Feng, and V. Vedral, Experimental verification of a Jarzynski-related information-theoretic equality by a single trapped ion, Phys. Rev. Lett. 120, 010601 (2018).
- A. Smith, Y. Lu, S. An, X. Zhang, J.-N. Zhang, Z. Gong, H. T. Quan, C. Jarzynski, and K. Kim, Verification of the quantum nonequilibrium work relation in the presence of decoherence, New J. Phys. 20, 013008 (2018).
- M. Naghiloo, M. Abbasi, Y. N. Joglekar, and K. W. Murch, Quantum state tomography across the exceptional point in a single dissipative qubit, Nat. Phys. 15, 1232 (2019).
- M. Abbasi, W. Chen, M. Naghiloo, Y. N. Joglekar, and K. W. Murch, Topological quantum state control through exceptional-point proximity, Phys. Rev. Lett. 128, 160401 (2022).
- D. C. Brody and E.-M. Graefe, Mixed-state evolution in the presence of gain and loss, Phys. Rev. Lett. 109, 230405 (2012).
- Z. Bian, L. Xiao, K. Wang, F. A. Onanga, F. Ruzicka, W. Yi, Y. N. Joglekar, and P. Xue, Quantum information dynamics in a high-dimensional parity-time-symmetric system, Phys. Rev. A 102, 030201(R) (2020).
- S. Deffner and A. Saxena, Jarzynski equality in -symmetric quantum mechanics, Phys. Rev. Lett. 114, 150601 (2015).
- B. Gardas, S. Deffner, and A. Saxena, Non-Hermitian quantum thermodynamics, Sci. Rep. 6, 23408 (2016).
- M. Zeng and E. H. Yong, Crooks fluctuation theorem in -symmetric quantum mechanics, J. Phys. Commun. 1, 031001 (2017).
- B.-B. Wei, Quantum work relations and response theory in parity-time-symmetric quantum systems, Phys. Rev. E 97, 012114 (2018).
- B.-B. Wei, Links between dissipation and Rényi divergences in -symmetric quantum mechanics, Phys. Rev. A 97, 012105 (2018).
- Z.-Y. Zhou, Z.-L. Xiang, J. Q. You, and F. Nori, Work statistics in non-Hermitian evolutions with Hermitian endpoints, Phys. Rev. E 104, 034107 (2021).
- K. Mølmer, Y. Castin, and J. Dalibard, Monte Carlo wave-function method in quantum optics, J. Opt. Soc. Am. B 10, 524 (1993).
- J. Dalibard, Y. Castin, and K. Mølmer, Wave-function approach to dissipative processes in quantum optics, Phys. Rev. Lett. 68, 580 (1992).
- C. M. Bender and S. Boettcher, Real spectra in non-Hermitian Hamiltonians having symmetry, Phys. Rev. Lett. 80, 5243 (1998).
- B. Peng, Ş. K. Özdemir, F. Lei, F. Monifi, M. Gianfreda, G. L. Long, S. Fan, F. Nori, C. M. Bender, and L. Yang, Parity-time-symmetric whispering-gallery microcavities, Nat. Phys. 10, 394 (2014).
- Ş. K. Özdemir, S. Rotter, F. Nori, and L. Yang, Parity-time symmetry and exceptional points in photonics, Nat. Mater. 18, 783 (2019).
- A. Guo, G. J. Salamo, D. Duchesne, R. Morandotti, M. Volatier-Ravat, V. Aimez, G. A. Siviloglou, and D. N. Christodoulides, Observation of -symmetry breaking in complex optical potentials, Phys. Rev. Lett. 103, 093902 (2009).
- C. E. Rüter, K. G. Makris, R. El-Ganainy, D. N. Christodoulides, M. Segev, and D. Kip, Observation of parity-time symmetry in optics, Nat. Phys. 6, 192 (2010).
- H. Hodaei, M.-A. Miri, M. Heinrich, D. N. Christodoulides, and M. Khajavikhan, Parity-time-symmetric microring lasers, Science 346, 975 (2014).
- L. Xiao, X. Zhan, Z. H. Bian, K. K. Wang, X. Zhang, X. P. Wang, J. Li, K. Mochizuki, D. Kim, N. Kawakami, W. Yi, H. Obuse, B. C. Sanders, and P. Xue, Observation of topological edge states in parity-time-symmetric quantum walks, Nat. Phys. 13, 1117 (2017).
- J. Li, A. K. Harter, J. Liu, L. de Melo, Y. N. Joglekar, and L. Luo, Observation of parity-time symmetry breaking transitions in a dissipative Floquet system of ultracold atoms, Nat. Commun. 10, 855 (2019).
- H. Xu, D. Mason, L. Jiang, and J. G. E. Harris, Topological energy transfer in an optomechanical system with exceptional points, Nature (London) 537, 80 (2016).
- W. Liu, Y. Wu, C.-K. Duan, X. Rong, and J. Du, Dynamically encircling an exceptional point in a real quantum system, Phys. Rev. Lett. 126, 170506 (2021).
- H. Hodaei, A. U. Hassan, S. Wittek, H. Garcia-Gracia, R. El-Ganainy, D. N. Christodoulides, and M. Khajavikhan, Enhanced sensitivity at higher-order exceptional points, Nature (London) 548, 187 (2017).
- W. Chen, Ş. K. Özdemir, G. Zhao, J. Wiersig, and L. Yang, Exceptional points enhance sensing in an optical microcavity, Nature (London) 548, 192 (2017).
- A. V. Varma, J. E. Muldoon, S. Paul, Y. N. Joglekar, and S. Das, Extreme violation of the Leggett-Garg inequality in nonunitary dynamics with complex energies, Phys. Rev. A 108, 032202 (2023).
- A. E. Rastegin and K. Życzkowski, Jarzynski equality for quantum stochastic maps, Phys. Rev. E 89, 012127 (2014).
- M.-A. Miri and A. Alù, Exceptional points in optics and photonics, Science 363, eaar7709 (2019).
- F. Klauck, L. Teuber, M. Ornigotti, M. Heinrich, S. Scheel, and A. Szameit, Observation of PT-symmetric quantum interference, Nat. Photonics 13, 883 (2019).
- Y. Wu, W. Liu, J. Geng, X. Song, X. Ye, C.-K. Duan, X. Rong, and J. Du, Observation of parity-time symmetry breaking in a single-spin system, Science 364, 878 (2019).
- L. Ding, K. Shi, Q. Zhang, D. Shen, X. Zhang, and W. Zhang, Experimental determination of -symmetric exceptional points in a single trapped ion, Phys. Rev. Lett. 126, 083604 (2021).
- N. Maraviglia, P. Yard, R. Wakefield, J. Carolan, C. Sparrow, L. Chakhmakhchyan, C. Harrold, T. Hashimoto, N. Matsuda, A. K. Harter, Y. N. Joglekar, and A. Laing, Photonic quantum simulations of coupled -symmetric Hamiltonians, Phys. Rev. Res. 4, 013051 (2022).
- J. Liphardt, S. Dumont, S. B. Smith, I. Tinoco, and C. Bustamante, Equilibrium information from nonequilibrium measurements in an experimental test of Jarzynski's equality, Science 296, 1832 (2002).
- O.-P. Saira, Y. Yoon, T. Tanttu, M. Möttönen, D. V. Averin, and J. P. Pekola, Test of the Jarzynski and Crooks fluctuation relations in an electronic system, Phys. Rev. Lett. 109, 180601 (2012).
- F. W. J. Hekking and J. P. Pekola, Quantum jump approach for work and dissipation in a two-level system, Phys. Rev. Lett. 111, 093602 (2013).
- J. P. Pekola, Y. Masuyama, Y. Nakamura, J. Bergli, and Y. M. Galperin, Dephasing and dissipation in qubit thermodynamics, Phys. Rev. E 91, 062109 (2015).
- S. Toyabe, T. Sagawa, M. Ueda, E. Muneyuki, and M. Sano, Experimental demonstration of information-to-energy conversion and validation of the generalized Jarzynski equality, Nat. Phys. 6, 988 (2010).
- Z. Gong, Y. Ashida, and M. Ueda, Quantum-trajectory thermodynamics with discrete feedback control, Phys. Rev. A 94, 012107 (2016).
- Y. Masuyama, K. Funo, Y. Murashita, A. Noguchi, S. Kono, Y. Tabuchi, R. Yamazaki, M. Ueda, and Y. Nakamura, Information-to-work conversion by Maxwell's demon in a superconducting circuit quantum electrodynamical system, Nat. Commun. 9, 1291 (2018).
- M. Naghiloo, J. J. Alonso, A. Romito, E. Lutz, and K. W. Murch, Information gain and loss for a quantum Maxwell's demon, Phys. Rev. Lett. 121, 030604 (2018).
- X. Song, M. Naghiloo, and K. Murch, Quantum process inference for a single-qubit Maxwell demon, Phys. Rev. A 104, 022211 (2021).
- X. Linpeng, L. Bresque, M. Maffei, A. N. Jordan, A. Auffèves, and K. W. Murch, Energetic cost of measurements using quantum, coherent, and thermal light, Phys. Rev. Lett. 128, 220506 (2022).
- A. K. Harter and Y. N. Joglekar, Connecting active and passive -symmetric Floquet modulation models, Prog. Theor. Exp. Phys. 2020, 12A106 (2020).