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Title: Quantum counting algorithm and its application in mesoscopic physics

Journal Article · · Physical Review. A
 [1];  [2];  [3]
  1. L. D. Landau Institute for Theoretical Physics RAS, 117940 Moscow (Russian Federation)
  2. Moscow Institute of Physics and Technology, Institutskii per. 9, 141700 Dolgoprudny, Moscow District (Russian Federation)
  3. Theoretische Physik, ETH-Zurich, CH-8093 Zuerich (Switzerland)

We discuss a quantum counting algorithm which transforms a physical particle-number state (and superpositions thereof) into a binary number. The algorithm involves two quantum Fourier transformations. One transformation is in physical space, where a stream of n<N=2{sup K} (charged) particles is coupled to K qubits, rotating their states by prescribed angles. The second transformation is within the Hilbert space of qubits and serves to read out the particle number in a binary form. Applications include a divisibility check characterizing the size of a finite train of particles in a quantum wire and a scheme allowing one to entangle multiparticle wave functions in a Mach-Zehnder interferometer, generating Bell, Greenberger-Horne-Zeilinger, or Dicke states.

OSTI ID:
21440483
Journal Information:
Physical Review. A, Vol. 82, Issue 1; Other Information: DOI: 10.1103/PhysRevA.82.012316; (c) 2010 The American Physical Society; ISSN 1050-2947
Country of Publication:
United States
Language:
English