Abstract
A convergence theorem is obtained for quantum random walks with particles in an arbitrary normal state. This unifies and extends previous work on repeated-interactions models, including that of Attal and Pautrat (Ann Henri Poincaré 7:59–104 2006) and Belton (J Lond Math Soc 81:412–434, 2010; Commun Math Phys 300:317–329, 2010). When the random-walk generator acts by ampliation and either multiplication or conjugation by a unitary operator, it is shown that the quantum stochastic cocycle which arises in the limit is driven by a unitary process.
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References
Attal S., Joye A.: The Langevin equation for a quantum heat bath. J. Funct. Anal. 247(2), 253–288 (2007)
Attal S., Joye A.: Weak coupling and continuous limits for repeated quantum interactions. J. Stat. Phys. 126(6), 1241–1283 (2007)
Attal S., Pautrat Y.: From repeated to continuous quantum interactions. Ann. Henri Poincaré 7(1), 59–104 (2006)
Belton, A.C.R.: Approximation via toy Fock space—the vacuum-adapted viewpoint. In: Belavkin, V.P., Guţă, M. (eds.) Quantum Stochastics and Information. Singapore: World Scientific, 2008, pp. 3–22
Belton A.C.R.: Random-walk approximation to vacuum cocycles. J. London Math. Soc. (2) 81(2), 412–434 (2010)
Belton A.C.R.: Quantum random walks and thermalisation. Commun. Math. Phys. 300(2), 317–329 (2010)
Bouten L., van Handel R., James M.R.: A discrete invitation to quantum filtering and feedback control. SIAM Rev. 51(2), 239–316 (2009)
Bruneau L., Joye A., Merkli M.: Asymptotics of repeated interaction quantum systems. J. Funct. Anal. 239(1), 310–344 (2006)
Bruneau L., Pillet C.-A.: Thermal relaxation of a QED cavity. J. Stat. Phys. 134(5–6), 1071–1095 (2009)
Gohm R.: Non-commutative Markov chains and multi-analytic operators. J. Math. Anal. Appl. 364(1), 275–288 (2010)
Gough J.: Holevo-ordering and the continuous-time limit for open Floquet dynamics. Lett. Math. Phys. 67(3), 207–221 (2004)
Gough J., James M.R.: The series product and its application to quantum feedforward and feedback networks. IEEE Trans. Automat. Control 54(11), 2530–2544 (2009)
Lindsay, J.M.: Quantum stochastic analysis—an introduction. In: Schürmann, M., Franz, U. (eds.) Quantum Independent Increment Processes I. Lecture Notes in Math. Vol. 1865, Berlin: Springer, 2005, pp. 181–271
Lindsay J.M., Wills S.J.: Existence, positivity and contractivity for quantum stochastic flows with infinite dimensional noise. Prob. Th. Rel. Fields 116(4), 505–543 (2000)
Lindsay J.M., Wills S.J.: Existence of Feller cocycles on a C*-algebra. Bull. London Math. Soc. 33(5), 613–621 (2001)
Sahu L.: Quantum random walks and their convergence to Evans–Hudson flows. Proc. Indian Acad. Sci. Math. Sci. 118(3), 443–465 (2008)
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Communicated by A. Connes
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Belton, A.C.R. Quantum Random Walks with General Particle States. Commun. Math. Phys. 328, 573–596 (2014). https://doi.org/10.1007/s00220-014-1886-3
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DOI: https://doi.org/10.1007/s00220-014-1886-3