Generative Data Intelligence

Ergodicity probes: using time-fluctuations to measure the Hilbert space dimension

Date:


Charlie Nation1 and Diego Porras2

1Department of Physics and Astronomy, University of Sussex, Brighton, BN1 9QH, United Kingdom.
2Institute of Fundamental Physics, IFF-CSIC, Calle Serrano 113b, 28006 Madrid, Spain

Find this paper interesting or want to discuss? Scite or leave a comment on SciRate.

Abstract

Quantum devices, such as quantum simulators, quantum annealers, and quantum computers, may be exploited to solve problems beyond what is tractable with classical computers. This may be achieved as the Hilbert space available to perform such `calculations’ is far larger than that which may be classically simulated. In practice, however, quantum devices have imperfections, which may limit the accessibility to the whole Hilbert space. We thus determine that the dimension of the space of quantum states that are available to a quantum device is a meaningful measure of its functionality, though unfortunately this quantity cannot be directly experimentally determined. Here we outline an experimentally realisable approach to obtaining the required Hilbert space dimension of such a device to compute its time evolution, by exploiting the thermalization dynamics of a probe qubit. This is achieved by obtaining a fluctuation-dissipation theorem for high-temperature chaotic quantum systems, which facilitates the extraction of information on the Hilbert space dimension via measurements of the decay rate, and time-fluctuations.

In this article we outline a method to exploit the dynamics of chaotic quantum systems to characterize quantum devices, such as quantum computers. We develop a theoretical model of quantum chaos in isolated systems, and propose that by watching the dynamics, one can obtain information on the complexity of the system from simple measurable quantities. There is a lot of interest at the moment in showing that a given quantum device may outperform regular computers in some meaningful way, though the comparison is not always obvious. Here we develop a method of quantifying the complexity of calculated quantum dynamics on such a device, for a comparison to be made. Further, this article contributes to theoretical developments in the thermalization of closed quantum systems, an important problem in the foundations of quantum statistical physics.

► BibTeX data

► References

[1] Immanuel Bloch, Jean Dalibard, and Sylvain Nascimbène. Quantum simulations with ultracold quantum gases. 8 (4): 267-276, 2012. https:/​/​doi.org/​10.1038/​nphys2259.
https:/​/​doi.org/​https:/​/​doi.org/​10.1038/​nphys2259

[2] Maciej Lewenstein, Anna Sanpera, and Veronica Ahufinger. Ultracold Atoms in Optical Lattices: Simulating quantum many-body systems. Oxford University Press, 2012. https:/​/​doi.org/​10.1080/​00107514.2013.800135.
https:/​/​doi.org/​https:/​/​doi.org/​10.1080/​00107514.2013.800135

[3] M Aidelsburger, J. L. Ville, R Saint-Jalm, S. Nascimbène, J Dalibard, and J Beugnon. Relaxation Dynamics in the Merging of N Independent Condensates. Phys. Rev. Lett., 119 (19): 190403, 2017. https:/​/​doi.org/​10.1103/​PhysRevLett.119.190403.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevLett.119.190403

[4] D. Porras and J. I. Cirac. Effective quantum spin systems with trapped ions. Phys. Rev. Lett., 92: 207901, May 2004. https:/​/​doi.org/​10.1103/​PhysRevLett.92.207901.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevLett.92.207901

[5] Ch Schneider, Diego Porras, and Tobias Schaetz. Experimental quantum simulations of many-body physics with trapped ions. Rep. Prog. Phys., 75 (2): 024401, jan 2012. https:/​/​doi.org/​10.1088/​0034-4885/​75/​2/​024401.
https:/​/​doi.org/​https:/​/​doi.org/​10.1088/​0034-4885/​75/​2/​024401

[6] R Blatt and C F Roos. Quantum simulations with trapped ions. Nature Physics, 8 (4): 277-284, 2012. https:/​/​doi.org/​10.1038/​nphys2252.
https:/​/​doi.org/​https:/​/​doi.org/​10.1038/​nphys2252

[7] Govinda Clos, Diego Porras, Ulrich Warring, and Tobias Schaetz. Time-Resolved Observation of Thermalization in an Isolated Quantum System. Phys. Rev. Lett., 117 (17): 1-6, 2016. https:/​/​doi.org/​10.1103/​PhysRevLett.117.170401.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevLett.117.170401

[8] Hyosub Kim, Yeje Park, Kyungtae Kim, H. S. Sim, and Jaewook Ahn. Detailed Balance of Thermalization dynamics in Rydberg atom quantum simulators. Phys. Rev. Lett., 120 (18): 180502, 2018. https:/​/​doi.org/​10.1103/​PhysRevLett.120.180502.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevLett.120.180502

[9] Hannes Bernien, Sylvain Schwartz, Alexander Keesling, Harry Levine, Ahmed Omran, Hannes Pichler, Soonwon Choi, Alexander S Zibrov, Manuel Endres, Markus Greiner, Vladan Vuletic, and Mikhail D Lukin. Probing many-body dynamics on a 51-atom quantum simulator. Nature, 551 (7682): 579-584, 2017. https:/​/​doi.org/​10.1038/​nature24622.
https:/​/​doi.org/​https:/​/​doi.org/​10.1038/​nature24622

[10] C Neill, P Roushan, M Fang, Y. Chen, M Kolodrubetz, Z Chen, A Megrant, R Barends, B Campbell, B Chiaro, A Dunsworth, E. Jeffrey, J Kelly, J Mutus, P. J.J. O’Malley, C Quintana, D Sank, A Vainsencher, J Wenner, T C White, A Polkovnikov, and J M Martinis. Ergodic dynamics and thermalization in an isolated quantum system. Nature Physics, 12 (11): 1037-1041, 2016. https:/​/​doi.org/​10.1038/​nphys3830.
https:/​/​doi.org/​https:/​/​doi.org/​10.1038/​nphys3830

[11] P Roushan, E Lucero, John M Martinis, B Chiaro, A Megrant, K Kechedzhi, A Dunsworth, J Wenner, P Klimov, B Burkett, K Arya, A Vainsencher, J Mutus, H Neven, A Fowler, Z Chen, Y. Chen, R Barends, S V Isakov, M Giustina, T Huang, J Kelly, M Neeley, T C White, S Boixo, D Sank, B Foxen, V Smelyanskiy, R Graff, E Jeffrey, C Quintana, and C Neill. A blueprint for demonstrating quantum supremacy with superconducting qubits. Science, 360 (6385): 195-199, 2018. https:/​/​doi.org/​10.1126/​science.aao4309.
https:/​/​doi.org/​https:/​/​doi.org/​10.1126/​science.aao4309

[12] Artur S L Malabarba, Luis Pedro Garcia-Pintos, Noah Linden, Terence C. Farrelly, and Anthony J Short. Quantum systems equilibrate rapidly for most observables. Phys. Rev. E, 90 (1), 2014. https:/​/​doi.org/​10.1103/​PhysRevE.90.012121.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevE.90.012121

[13] Luis Pedro García-Pintos, Noah Linden, Artur S.L. Malabarba, Anthony J Short, and Andreas Winter. Equilibration time scales of physically relevant observables. Phys. Rev. X, 7 (3), 2017. https:/​/​doi.org/​10.1103/​PhysRevX.7.031027.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevX.7.031027

[14] Jonas Richter, Jochen Gemmer, and Robin Steinigeweg. Impact of eigenstate thermalization on the route to equilibrium. Phys. Rev. E, 99: 050104, May 2019. https:/​/​doi.org/​10.1103/​PhysRevE.99.050104.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevE.99.050104

[15] Thiago R. De Oliveira, Christos Charalambous, Daniel Jonathan, Maciej Lewenstein, and Arnau Riera. Equilibration time scales in closed many-body quantum systems. New J. Phys., 20 (3): 33032, 2018. https:/​/​doi.org/​10.1088/​1367-2630/​aab03b.
https:/​/​doi.org/​https:/​/​doi.org/​10.1088/​1367-2630/​aab03b

[16] Fausto Borgonovi, Felix M Izrailev, and Lea F Santos. Exponentially fast dynamics in the Fock space of chaotic many-body systems. Phys. Rev. E, 99 (1): 010101(R), 2019. https:/​/​doi.org/​10.1103/​PhysRevE.99.010101.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevE.99.010101

[17] Mauro Schiulaz, E Jonathan Torres-Herrera, and Lea F Santos. Thouless and Relaxation Time Scales in Many-Body Quantum Systems. Phys. Rev. B, 99 (17): 174313, 2019a. https:/​/​doi.org/​10.1103/​PhysRevB.99.174313.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevB.99.174313

[18] Álvaro M. Alhambra, Jonathon Riddell, and Luis Pedro García-Pintos. Time evolution of correlation functions in quantum many-body systems. 2019. URL http:/​/​arxiv.org/​abs/​1906.11280.
arXiv:1906.11280

[19] Mark Srednicki. Chaos and quantum thermalization. Phys. Rev. E, 50 (2): 888-901, 1994. https:/​/​doi.org/​10.1103/​PhysRevE.50.888.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevE.50.888

[20] Mark Srednicki. The approach to thermal equilibrium in quantized chaotic systems. J. Phys. A: Math. Gen., 32 (3299): 1163-1175, 1999. https:/​/​doi.org/​10.1088/​0305-4470/​32/​7/​007.
https:/​/​doi.org/​https:/​/​doi.org/​10.1088/​0305-4470/​32/​7/​007

[21] Marcos Rigol, Vanja Dunjko, and Maxim Olshanii. Thermalization and its mechanism for generic isolated quantum systems. Nature, 452 (7189): 854-858, 2008. https:/​/​doi.org/​10.1038/​nature06838.
https:/​/​doi.org/​https:/​/​doi.org/​10.1038/​nature06838

[22] Peter Reimann. Foundation of statistical mechanics under experimentally realistic conditions. Phys. Rev. Lett., 101 (19), 2008. https:/​/​doi.org/​10.1103/​PhysRevLett.101.190403.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevLett.101.190403

[23] V. I. Yukalov. Equilibration and thermalization in finite quantum systems. Laser Physics Letters, 8 (7): 485-507, 2011. https:/​/​doi.org/​10.1002/​lapl.201110002.
https:/​/​doi.org/​https:/​/​doi.org/​10.1002/​lapl.201110002

[24] Marcos Rigol and Mark Srednicki. Alternatives to eigenstate thermalization. Phys. Rev. Lett., 108 (11): 1-5, 2012. https:/​/​doi.org/​10.1103/​PhysRevLett.108.110601.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevLett.108.110601

[25] Luca D’Alessio, Yariv Kafri, Anatoli Polkovnikov, and Marcos Rigol. From quantum chaos and eigenstate thermalization to statistical mechanics and thermodynamics. Advances in Physics, 65 (3): 239-362, 2016. https:/​/​doi.org/​10.1080/​00018732.2016.1198134.
https:/​/​doi.org/​https:/​/​doi.org/​10.1080/​00018732.2016.1198134

[26] Wouter Beugeling, R Moessner, and Masudul Haque. Finite-size scaling of eigenstate thermalization. Phys. Rev. E, 89 (4), 2014. https:/​/​doi.org/​10.1103/​PhysRevE.89.042112.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevE.89.042112

[27] Wouter Beugeling, Roderich Moessner, and Masudul Haque. Off-diagonal matrix elements of local operators in many-body quantum systems. Phys. Rev. E, 91 (1), 2015. https:/​/​doi.org/​10.1103/​PhysRevE.91.012144.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevE.91.012144

[28] J Eisert, M Friesdorf, and C Gogolin. Quantum many-body systems out of equilibrium. Nature Physics, 11 (2): 124-130, 2014. https:/​/​doi.org/​10.1038/​nphys3215.
https:/​/​doi.org/​https:/​/​doi.org/​10.1038/​nphys3215

[29] Fabio Anza, Christian Gogolin, and Marcus Huber. Eigenstate Thermalization for Degenerate Observables. Phys. Rev. Lett., 120 (15), 2018. https:/​/​doi.org/​10.1103/​PhysRevLett.120.150603.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevLett.120.150603

[30] Joshua M Deutsch. Eigenstate thermalization hypothesis. Rep. Prog. Phys., 81 (8): 082001, 2018. https:/​/​doi.org/​10.1088/​1361-6633/​aac9f1.
https:/​/​doi.org/​https:/​/​doi.org/​10.1088/​1361-6633/​aac9f1

[31] Zeeya Merali. The new thermodynamics: how quantum physics is bending the rules. Nature, 551: 20-22, 2017. https:/​/​doi.org/​10.1038/​551020a.
https:/​/​doi.org/​https:/​/​doi.org/​10.1038/​551020a

[32] Marcos Rigol. Quantum quenches and thermalization in one-dimensional fermionic systems. Phys. Rev. A, 80 (5), 2009. https:/​/​doi.org/​10.1103/​PhysRevA.80.053607.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevA.80.053607

[33] Peter Reimann. Typical fast thermalization processes in closed many-body systems. Nature Communications, 7, 2016. https:/​/​doi.org/​10.1038/​ncomms10821.
https:/​/​doi.org/​https:/​/​doi.org/​10.1038/​ncomms10821

[34] Fausto Borgonovi, F. M. Izrailev, Lea F Santos, and V. G. Zelevinsky. Quantum chaos and thermalization in isolated systems of interacting particles. Physics Reports, 626: 1-58, 2016. https:/​/​doi.org/​10.1016/​j.physrep.2016.02.005.
https:/​/​doi.org/​https:/​/​doi.org/​10.1016/​j.physrep.2016.02.005

[35] Lennart Dabelow and Peter Reimann. Perturbed relaxation of quantum many-body systems. 2019. URL http:/​/​arxiv.org/​abs/​1903.11881.
arXiv:1903.11881

[36] Peter Reimann and Lennart Dabelow. Typicality of Prethermalization. Phys. Rev. Lett., 122 (8), 2019. https:/​/​doi.org/​10.1103/​PhysRevLett.122.080603.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevLett.122.080603

[37] Eduardo Jonathan Torres-Herrera, Jonathan Karp, Marco Tavora, and Lea F Santos. Realistic many-body quantum systems vs. full random matrices: Static and dynamical properties. Entropy, 18 (10), 2016. https:/​/​doi.org/​10.3390/​e18100359.
https:/​/​doi.org/​https:/​/​doi.org/​10.3390/​e18100359

[38] Ryusuke Hamazaki and Masahito Ueda. Random-matrix behavior of quantum nonintegrable many-body systems with dyson’s three symmetries. Phys. Rev. E, 99: 042116, 2019. https:/​/​doi.org/​10.1103/​PhysRevE.99.042116.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevE.99.042116

[39] R Kubo. The fluctuation-dissipation theorem. Rep. Prog. Phys., 29 (1): 255, 1966. https:/​/​doi.org/​10.1088/​0034-4885/​29/​1/​306.
https:/​/​doi.org/​https:/​/​doi.org/​10.1088/​0034-4885/​29/​1/​306

[40] Charlie Nation and Diego Porras. Off-diagonal observable elements from random matrix theory: Distributions, fluctuations, and eigenstate thermalization. New J. Phys., 20 (10): 103003, 2018. https:/​/​doi.org/​10.1088/​1367-2630/​aae28f.
https:/​/​doi.org/​https:/​/​doi.org/​10.1088/​1367-2630/​aae28f

[41] Charlie Nation and Diego Porras. Quantum chaotic fluctuation-dissipation theorem: Effective Brownian motion in closed quantum systems. Phys. Rev. E, 99 (5): 052139, 2019a. https:/​/​doi.org/​10.1103/​PhysRevE.99.052139.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevE.99.052139

[42] Phillip Weinberg and Marin Bukov. QuSpin: a Python Package for Dynamics and Exact Diagonalisation of Quantum Many Body Systems part I: spin chains. SciPost Phys, 2: 003, 2016. https:/​/​doi.org/​10.21468/​SciPostPhys.2.1.003.
https:/​/​doi.org/​https:/​/​doi.org/​10.21468/​SciPostPhys.2.1.003

[43] Phillip Weinberg and Marin Bukov. QuSpin: a Python Package for Dynamics and Exact Diagonalisation of Quantum Many Body Systems part I: spin chains. SciPost Phys., 2: 003, 2017. https:/​/​doi.org/​10.21468/​SciPostPhys.2.1.003.
https:/​/​doi.org/​https:/​/​doi.org/​10.21468/​SciPostPhys.2.1.003

[44] J. M. Deutsch. Quantum statistical mechanics in a closed system. Phys. Rev. A, 43 (4): 2046-2049, 1991a. https:/​/​doi.org/​10.1103/​PhysRevA.43.2046.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevA.43.2046

[45] J. M. Deutsch. A closed quantum system giving ergodicity. (unpublished), 1991b. URL https:/​/​deutsch.physics.ucsc.edu/​pdf/​quantumstat.pdf.
https:/​/​deutsch.physics.ucsc.edu/​pdf/​quantumstat.pdf

[46] Peter Reimann. Eigenstate thermalization: Deutsch’s approach and beyond. New J. Phys., 17 (5), 2015. https:/​/​doi.org/​10.1088/​1367-2630/​17/​5/​055025.
https:/​/​doi.org/​https:/​/​doi.org/​10.1088/​1367-2630/​17/​5/​055025

[47] Ralf R Müller. Random matrices, free probability and the replica method. In European Signal Processing Conference, volume 06-10-Sept, pages 189-196, 2015. ISBN 9783200001657. URL https:/​/​ieeexplore.ieee.org/​document/​7079688.
https:/​/​ieeexplore.ieee.org/​document/​7079688

[48] Mauro Schiulaz, E Jonathan Torres-Herrera, Francisco Pérez-Bernal, and Lea F Santos. Self-averaging in many-body quantum systems out of equilibrium. 2019b. URL http:/​/​arxiv.org/​abs/​1906.11856.
arXiv:1906.11856

[49] Charlie Nation and Diego Porras. Non-ergodic quantum thermalization. 2019b. URL https:/​/​arxiv.org/​pdf/​1908.11773.pdf.
https:/​/​arxiv.org/​pdf/​1908.11773.pdf

[50] Amnon Aharony and A Brooks Harris. Absence of self-averaging and universal fluctuations in random systems near critical points. Phys. Rev. Lett., 77 (18): 3700-3703, 1996. https:/​/​doi.org/​10.1103/​PhysRevLett.77.3700.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevLett.77.3700

[51] Giorgio Parisi and Nicolas Sourlas. Scale Invariance in Disordered Systems: The Example of the Random-Field Ising Model. Phys. Rev. Lett., 89 (25), 2002. https:/​/​doi.org/​10.1103/​PhysRevLett.89.257204.
https:/​/​doi.org/​https:/​/​doi.org/​10.1103/​PhysRevLett.89.257204

Cited by

[1] Phillip Weinberg and Marin Bukov, “QuSpin: a Python package for dynamics and exact diagonalisation of quantum many body systems. Part II: bosons, fermions and higher spins”, SciPost Physics 7 2, 020 (2019).

[2] Charlie Nation and Diego Porras, “Non-ergodic quantum thermalization”, arXiv:1908.11773.

The above citations are from SAO/NASA ADS (last updated successfully 2020-01-22 20:11:26). The list may be incomplete as not all publishers provide suitable and complete citation data.

On Crossref’s cited-by service no data on citing works was found (last attempt 2020-01-22 20:11:24).

Source: https://quantum-journal.org/papers/q-2019-12-02-207/

spot_img

Latest Intelligence

spot_img