It from Bit from It from Bit ... Nature and Nonlinear Logic

Pierre Alix Deymier, Keith Runge, M. Arif Hasan +2 more

We experimentally navigate the Hilbert space of two logical phi-bits supported by an externally driven nonlinear array of coupled acoustic waveguides by parametrically changing the relative phase of the drivers. We observe sharp phase jumps of approximately 180° in the individual phi-bit states as a result of the phase tuning of the drivers. The occurrence of these sharp phase jumps varies from phi-bit to phi-bit. All phi-bit phases also possess a common background dependency on the drivers’ phase. Within the context of multiple time scale perturbation theory, we develop a simple model of the nonlinear array of externally driven coupled acoustic waveguides to shed light on the possible mechanisms for the experimentally observed behavior of the logical phi-bit phase. Finally, we illustrate the ability to experimentally initialize the state of single- and multiple- phi-bit systems by exploiting the drivers’ phase as a tuning parameter. We also show that the nonlinear correlation between phi-bits enables parallelism in the manipulation of two- and multi-phi-bit superpositions of states.

Anthony N. Aguirre, Brendan Foster, Zeeya Merali

Ali Barzegar, Afshin Shafiee, Mostafa Taqavi

Yu‐Bo Sheng, Zhou, Lan

Logic-qubit entanglement has attracted much attention in both quantum communication and quantum computation. Here, we present an efficient protocol to distill the logic-qubit entanglement with the help of cross-Kerr nonlinearity. This protocol not only can purify the logic bit-flip error and logic phase-flip error, but also can correct the physical bit-flip error completely. We use cross-Kerr nonlinearity to construct quantum nondemolition detectors. Our distillation protocol for logic-qubit entanglement may be useful for the practical applications in quantum information, especially in long-distance quantum communication.

Alexander A. Berezin

Georgy M. Safiullin, Victor G. Nikiforov, Vladimir S. Lobkov +2 more

We realized a logical function of bit-to-bit parallel multiplication for optical echo-processor based on the third-order nonlinear optical response of a resonant medium at room temperature. As an operating medium we used the polyvinilbutural film doped with phthalocyanine dye. The result of the logical operation is presented in the spectrum of the nonlinear optical response after action of the two spectrally coded pumping pulses. The time of the logical operation is about 500 fs. We obtained the values of a homogeneous broadening of S0 - S1 line: Γhom = 89 cm-1 at T = 300 K and Γhom = 44 cm-1 at T = 77 K. The laser excitation parameters needed for effective operating of optical processor are defined. The maximum word length achievable under current experimental conditions is estimated.