Realizing acoustic qubit analogues with nonlinearly tunable phi-bits in externally driven coupled acoustic waveguides

Abstract

Using experiments and theory, we investigate the behavior of nonlinear acoustic modes in a physical system composed of an array of three coupled acoustic waveguides, two of which are externally driven with two different frequencies. Nonlinear modes with frequency given by linear combinations of the driving frequencies are realizations of so-called logical phi-bits. A phi-bit is a two-state degree of freedom of an acoustic wave, which can be in a coherent superposition of states with complex amplitude coefficients, i.e., a qubit analogue. We demonstrate experimentally that phi-bit modes are supported in the array of waveguides. Using perturbation theory, we show that phi-bits may result from the intrinsic nonlinearity of the material used to couple the waveguides. We have also isolated possible effects on phi-bit states associated with the systems’ electronics, transducers and ultrasonic coupling agents used to probe the array and that may introduce extrinsic nonlinearities. These extrinsic effects are shown to be easily separable from the intrinsic behavior. The intrinsic behavior includes sharp jumps in phi-bit phases occurring over very narrow ranges of driving frequency. These jumps may also exhibit hysteretic behavior dependent on the direction of driving frequency tuning. The intrinsic states of phi-bits and multiple nonlinearly correlated phi-bits may serve as foundation for robust and practical quantum-analogue information technologies.

Classical Coherent States Based Quantum Information Processing and Quantum Computing Analogs

“…Inspired by recent findings that the classical states can be entangled [1], [2], the CNOT gate can be implemented using the classical acoustic qubit-analog [3], and that quantum parallelism can be achieved on classical quantum computing acoustic analog [4], in this paper we propose how to implement quantum information processing analogs in integrated optics based on classical polarization and OAM states.…”

“…Given that ref. [4] has already shown that certain quantum algorithms exploiting the quantum parallelism can be implemented in classical quantum computing acoustic analog platform, the existing quantum algorithms need to be revisited for the true quantum advantages. Further, the proposed classical optical quantum computing analogs do not require delicate quantum error correction.…”

“…Quantum parallelism is the capability to parallelly conduct a large number of operations. Recently, Deymier's group have shown that the quantum algorithms can be run on topological acoustic (TA)-based quantum analogs, which are essentially classical computers, and that the nonlinearity is a key enabler for so called quantum parallelism [2]- [4]. These recent findings have motivated us to revisit our previous QIP proposals for integrated optics implementations [11]- [19], but now in the context of optical quantum computing analogs.…”

Information encoding and encryption in acoustic analogues of qubits

“…The second behavior which is only occurring in the case of phi-bits 4 and 5 takes the form of sharp 180° ( ) jumps. The possible physical origin of these two behaviors has been discussed at length in references 14 . Here we focus on the first behavior by correcting the phase differences by the jumps to obtain continuous variations for all phi-bits.…”