Heralded generation of a micro-macro entangled state

Abstract

Using different optical setups based on squeezed state and photon subtraction we show how optical entanglement between a macroscopic and a microscopic state-the so-called Schrödinger cat state or micro-macro state-can be generated. The entangled state is heralded and is thus produced a priori in contrast to previous proposals. We define the macroscopicity of the macroscopic part of the state as their mean distance in phase space and the success rate in discriminating them with homodyne detection, and subsequently, based on these measures we investigate the macroscopicity of different states. Furthermore, we show that the state can be used to map a microscopic qubit onto a macroscopic one thereby linking a qubit processor with a qumode processor.

Generation of hybrid entanglement between a single-photon polarization qubit and a coherent state

“…Unlike previous proposals [8][9][10], our scheme enables one to generate the exact form of hybrid entanglement, without approximation, required for resourceefficient optical hybrid quantum computation [13] and loophole-free Bell inequality tests [12]. The required resources are an SCS, an entangled photon pair, the displacement operation, four photodetectors, and beam splitters.…”

“…An intriguing challenge in this subject is to entangle different types of states of light such as microscopic and macroscopic states or wavelike and particlelike states [1][2][3][4][5][6][7][8][9][10]. Some of those states have been found useful for quantum information applications [11][12][13][14].…”

Two different types of optical hybrid qubits for teleportation in a lossy environment

“…Since there are a number of studies on quantum information processing using various kinds of optical hybrid systems [21,30,31,[33][34][35][36][37][38][39][40][41][42][43], we first need to clarify the types of optical hybrid qubits that we consider in this paper. The first one is the hybrid of photon polarization with coherent states, which was originally used to propose the hybrid scheme of optical quantum information processing recently [21].…”

Quantum state engineering by click counting

“…Another prominent example for controlled state manipulation is noiseless amplification [43][44][45][46][47]. All these engineering processes are able to enhance quantum properties, such as entanglement, for applications in quantum information science, see, e.g., [48][49][50][51][52][53][54][55][56][57][58].…”