Generating superposition of up-to three photons for continuous variable quantum information processing

Abstract

Abstract:We develop an experimental scheme based on a continuouswave (cw) laser for generating arbitrary superpositions of photon number states. In this experiment, we successfully generate superposition states of zero to three photons, namely advanced versions of superpositions of two and three coherent states. They are fully compatible with developed quantum teleportation and measurement-based quantum operations with cw lasers. Due to achieved high detection efficiency, we observe, without any loss correction, multiple areas of negativity of Wigner function, which confirm strongly nonclassical nature of the generated states. Haroche, "Quantum Zeno dynamics of a field in a cavity," Phys. Rev. A 86, 032120 (2012).

Implementation of a quantum cubic gate by an adaptive non-Gaussian measurement

“…Here we consider preparing the ancillary state that can be generated within reach of current technologies. On one hand, arbitrary superpositions of photon-number states up to three photon level |ψ N =3 can be prepared [21,29], and the photon-number limit can be in principle incremented. On the other hand, we can perform universal Gaussian operationÛ G onto any input state [14][15][16].…”

“…On the other hand, the present state (25) is derived so that its overall suitability as the ancilla is maximized with suitable Gaussian operations. In either case, the state can be prepared by the same experimental method [21,29].…”

Conditional superpositions of Gaussian operations on different modes of light

“…These tw o-m ode X gates can be im plem ented by tw o local single-m ode X gates driven by ancillary states, K U = 4 ( l 1>A .I0U -*a," /jr|0>,1|lU ). (16) All these states can be easily prepared from sequential single photon states by splitting them on a balanced beam splitter with varying relative phase. This shows that single-photon states can be used not only for generation o f interesting single-m ode nonlinearities [13,34,35], but also for realization o f m ultim ode nonlinear transform ations.…”

“…First, quantum optics can manipulate combina tions of elementary building blocks-annihilation and creation operations [14,15]--flexibly and precisely. Second, quantum optics exploits high-fidelity and high-speed tomographic ho modyne measurements [16,17], which allow for a very precise observation of sensitive non-Gaussian quantum effects.…”

Nonclassical non-Gaussian state of a mechanical resonator via selectively incoherent damping in a three-mode optomechanical system

“…And the optomechanical systems are appraoching the strong single-photon coupling regime [29][30][31]. Thus the optomechanical systems provide a very good platform to explore the macroscopic quantum states of the MRs. And the quantum superpositions are main resources for quantum information processing [32]. Motivated by these reseaches, we use a three-mode optomechanical system to study the nonclassical phonon states engineering.…”