Extreme optical states
The toolbox of operations that are available for the manipulation of CV states have been recently extended with conditional photon subtraction, a process which enabled the generation of highly non-classical states of light with negative Wigner functions such as the single photon state and the Schrödinger cat state (see the box for explanation). This has opened access to the realm of non-Gaussian operations and states, which are essential to CV quantum processors. Of particular high importance is the non-Gaussian Schrödinger cat state since it serves as a resource for CV quantum computing.
The aim of the present proposed project is to fully exploit the potential of photon counting measurements combined with linear optics, homodyne detection and electro-optic feedforward. We will use these tools to generate highly non-Gaussian CV states and to design schemes for implementation of various non-linear quantum operations on light modes.
Coherent state Single photon state Schrödinger cat state
Gaussian and non-Gaussian states: Quantum states can be fully characterized by their Wigner function, W(x,p), which is a two dimensional quasi-probability distribution of the amplitude, x, and phase, p, of the light field. Simple light fields such as the coherent states (typically generated by a laser) are described by Gaussian and positive Wigner functions. The Wigner functions for highly non-classical states, such as the single photon state or the Schrodinger Cat state, show oscillations and negativities revealing pure quantum interference. These states are therefore referred to as non-Gaussian states and are resources for quantum information processors. |
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