Optical Quantum State Synthesis

K. L. Pregnell, David Thomas Pegg

Adam Miranowicz, Şahin Kaya Özdemir, J. Bajer +2 more

Selective truncation of the Fock-state expansion of an optical field can be achieved using projection synthesis. The process removes the predetermined Fock states from the input field by conditional measurement and teleportation. We present a scheme to perform projection synthesis based on multiport interferometry. This scheme can be used both as a generalized quantum scissors device that filters out Fock states with photon numbers higher than a predetermined value, and as a quantum punching device that selectively removes specific Fock states, making holes in the Fock-state expansion of the input field.

Ivan Deutsch, Poul Jessen

Jessen

Şahin Kaya Özdemir, Adam Miranowicz, Masato Koashi +1 more

Quantum projection synthesis can be used for phase-probability-distribution measurement and optical-state truncation and preparation. The method relies on interfering optical light beams, which is a major challenge in experiments performed by pulsed light sources. In the pulsed regime, the time frequency overlap of the interfering light beams has a major impact on the efficiency of the method. In this paper, the pulse-mode projection-synthesis approach is developed, the mode structures of interfering light beams are characterized, and the effect of this overlap on the fidelity of optical-state truncation and preparation is investigated. By introducing the positive-operator-valued measure for the detection events in the scheme, the effect of mode mismatch between the photon-counting detectors and the incident light beams is also presented.

Alberto Barchielli, Matteo Gregoratti