Universal state orthogonalizer and qubit generator

TL;DR

This paper presents a universal method to generate orthogonal states and superpositions of arbitrary pure quantum states, enabling flexible creation of optical qubits for quantum technologies.

Contribution

It introduces a novel, operational approach to produce orthogonal and superposed states from limited input information, applicable to continuous-variable optical qubits.

Findings

Successfully demonstrated universal orthogonalizer for quantum states

Able to generate arbitrary superpositions of orthogonal states

Potential applications in quantum measurement and information processing

Abstract

The superposition principle is at the heart of quantum mechanics and at the root of many paradoxes arising when trying to extend its predictions to our everyday world. Schroedinger's cat is the prototype of such paradoxes and here, in contrast to many others, we choose to investigate it from the operational point of view. We experimentally demonstrate a universal strategy for producing an unambiguously distinguishable type of superposition, that of an arbitrary pure state and its orthogonal. It relies on only a limited amount of information about the input state to first generate its orthogonal one. Then, a simple change in the experimental parameters is used to produce arbitrary superpositions of the mutually orthogonal states. Constituting a sort of Schroedinger's black box, able to turn a whole zoo of input states into coherent superpositions, our scheme can produce arbitrary continuous-variable optical qubits, which may prove practical for implementing quantum technologies and measurement tasks.