Quantum Computing and Quantum Communications

Volume 1509 of the series Lecture Notes in Computer Science pp 89-102


Correlation between Correlations: Process and Time in Quantum Networks

  • Günter MahlerAffiliated withInstitut für Theoretische Physik, Universität Stuttgart
  • , Ilki KimAffiliated withInstitut für Theoretische Physik, Universität Stuttgart


We study a special inhomogeneous quantum network consisting of a ring of M pseudo-spins (here M = 4) sequentially coupled to one and the same central spin under the influence of given pulse sequences (quantum gate operations). This architecture could be visualized as a quantum Turing machine with a cyclic “tape„. Rather than input-output-relations we investigate the resulting process, i.e. the correlation between one- and two-point expectation values (“correlations„) over various time-steps. The resulting spatiotemporal pattern exhibits many non-classical features including Zeno-effects, violation of temporal Bell-inequalities and quantum parallelism. Due to the strange web of correlations being built-up, specific measurement outcomes for the tape may refer to one or several preparation histories of the head. Specific families of correlation functions are more stable with respect to dissipation than the total wave-function.