Experimental demonstration of coherent superpositions in an ultrasonic pseudospin

Lazaro Calderin,Pierre Lucas,Keith Runge,Neil G Jenkins,Pierre A Deymier,M Arif Hasan,Trevor Lata

doi:10.1038/s41598-019-50366-y

Lazaro Calderin, Pierre Lucas + Show 5 more

Open Access

https://doi.org/10.1038/s41598-019-50366-y

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Journal: Scientific Reports	Publication Date: Oct 2, 2019
Citations: 12	License type: open-access

Affiliation: University of Arizona

Abstract

We experimentally demonstrate the existence and control of coherent superpositions of elastic states in the direction of propagation of an ultrasonic pseudospin i.e., a φ-bit. The experimental realization of this mechanical pseudospin consists of an elastic aluminum rod serving as a waveguide sandwiched between two heavy steel plates. The Hertzian contact between the rod and the plates leads to restoring forces which couple the directions of propagation (forward and backward). This coupling generates the coherence of the superposition of elastic states. We also demonstrate φ-bit gate operations on the coherent superposition analogous to those used in quantum computing. In the case of a φ-bit, the coherent superposition of states in the direction of propagation are immune to wave function collapse upon measurement as they result from classical waves.

Highlights

The quantum bit is the critical component of future quantum information processing platforms[1]
We have demonstrated experimentally the existence and control of coherent superpositions of elastic states in the direction of propagation of an ultrasonic pseudospin i.e., a φ-bit
The Hertzian contact between the plates and the rod establishes restoring forces which result in quasi-standing wave elastic longitudinal modes that can be represented as spinors in the space of the direction of propagation along the waveguide

Summary

Introduction

The quantum bit (qubit) is the critical component of future quantum information processing platforms[1]. Measurement on quantum systems in superposition of states leads to collapse of the wave function onto pure states, requiring the use of statistical approaches to determining the original superposition To overcome these critical drawbacks, one may call upon the notion of pseudospin which is a classical system that may exhibit properties isomorphic to true quantum spin systems. We proposed theoretically, the concept of a one-dimensional elastic pseudospin, which we called a φ-bit This elastic pseudospin is an elastic mechanical system in which the displacement field is describable by a wave function isomorphic to that of a quantum spin in that it possesses a spinorial character[15,16,17,18]. The spinor amplitudes have the form ss[12] ωk ωk βk βk with s1 and s2 taking on the values

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Discussion

Conclusion