Iterative Protocols for the Generation of new Quantum States of Light

Probabilistic heralded Gaussification of quantum states of light is an important ingredient of protocols for distillation of continuous variable entanglement and squeezing. An elementary step of the heralded Gaussification protocol consists of interference of two copies of the state at a balanced beam splitter, followed by conditioning on the outcome of a suitable Gaussian quantum measurement on one output mode. When iterated, the protocol either converges to a Gaussian state or diverges. Here, we report on experimental investigation of the convergence properties of iterative heralded Gaussification. We experimentally implement two iterations of the protocol, which requires simultaneous processing of four copies of the input state. We utilize the phase-randomized coherent states as the input states, which greatly facilitates the experiment because these states can be generated deterministically, and their mean photon number can easily be tuned. We comprehensively characterize the input and partially Gaussified states by balanced homodyne detection and quantum state tomography. Our experimental results are in good agreement with theoretical predictions and they provide new insights into the convergence properties of heralded quantum Gaussification.Probabilistic heralded Gaussification of quantum states of light is an important ingredient of protocols for distillation of continuous variable entanglement and squeezing. An elementary step of the heralded Gaussification protocol consists of interference of two copies of the state at a balanced beam splitter, followed by conditioning on the outcome of a suitable Gaussian quantum measurement on one output mode. When iterated, the protocol either converges to a Gaussian state or diverges. Here, we report on experimental investigation of the convergence properties of iterative heralded Gaussification. We experimentally implement two iterations of the protocol, which requires simultaneous processing of four copies of the input state. We utilize the phase-randomized coherent states as the input states, which greatly facilitates the experiment because these states can be generated deterministically, and their mean photon number can easily be tuned. We comprehensively characterize the input and partially Gaussified states by balanced homodyne detection and quantum state tomography. Our experimental results are in good agreement with theoretical predictions and they provide new insights into the convergence properties of heralded quantum Gaussification.

arXiv:2412.10970Optics ExpressNov 14, 20241 citation

Generation of squeezed Schrödinger cat states with an operation allowing iterative growth

Jean Etesse, Martin Bouillard, Bhaskar Kanseri +1 more

We present what is to our knowledge the first implementation of a Schrödinger cat states "breeding" operation, which allows an iterative growth of these states. We thus report the experimental generation of a squeezed Schrödinger cat state from two single photon Fock states, which can be seen as cat states with zero amplitude. These Fock states are mixed on a symmetrical beamsplitter and the generation is heralded by a homodyne measurement in one of the two output arms. The output state has a fidelity of 61% with an even squeezed Schrödinger cat state of amplitude $α=1.63$ . This hybrid operation opens up new prospects in quantum optics as the protocol depicted here can be iterated in order to produce new kind of mesoscopic states.We present what is to our knowledge the first implementation of a Schrödinger cat states "breeding" operation, which allows an iterative growth of these states. We thus report the experimental generation of a squeezed Schrödinger cat state from two single photon Fock states, which can be seen as cat states with zero amplitude. These Fock states are mixed on a symmetrical beamsplitter and the generation is heralded by a homodyne measurement in one of the two output arms. The output state has a fidelity of 61% with an even squeezed Schrödinger cat state of amplitude $α=1.63$. This hybrid operation opens up new prospects in quantum optics as the protocol depicted here can be iterated in order to produce new kind of mesoscopic states.

arXiv:1412.3219Dec 10, 20140 citations

Creation of Quantum States of Light

Akira Furusawa

SpringerBriefs in mathematical physicsJan 1, 20151 citation

Experimental Generation of Squeezed Cat States with an Operation Allowing Iterative Growth

Jean Etesse, Martin Bouillard, Bhaskar Kanseri +1 more

We present what is, to our knowledge, the first implementation of a "cat breeding" operation, which allows an iterative growth of cat states. We thus report the experimental generation of a squeezed cat state from two single photon Fock states, which can be seen as cat states with zero amplitude. These Fock states are mixed on a symmetrical beam splitter, and the generation is heralded by a homodyne measurement in one of the two output arms. The output state has a fidelity of 61% with an even squeezed cat state of amplitude α=1.63. This hybrid operation opens up new prospects in quantum optics, as the protocol depicted here can be iterated in order to produce new kinds of mesoscopic states.We present what is, to our knowledge, the first implementation of a "cat breeding" operation, which allows an iterative growth of cat states. We thus report the experimental generation of a squeezed cat state from two single photon Fock states, which can be seen as cat states with zero amplitude. These Fock states are mixed on a symmetrical beam splitter, and the generation is heralded by a homodyne measurement in one of the two output arms. The output state has a fidelity of 61% with an even squeezed cat state of amplitude α=1.63. This hybrid operation opens up new prospects in quantum optics, as the protocol depicted here can be iterated in order to produce new kinds of mesoscopic states.

Physical Review LettersMay 15, 2015125 citations

α=1.63

. This hybrid operation opens up new prospects in quantum optics as the protocol depicted here can be iterated in order to produce new kind of mesoscopic states.