Quantum Optics Seminar by Tobias Eberle – Niels Bohr Institute - University of Copenhagen

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Quantum Optics Seminar by Tobias Eberle

Continuous variable quantum key distribution was just recently proven composably secure against most general coherent attacks by using highly entangled two-mode squeezed states. On the way to experimentally realize this protocol, I will talk about the generation of EPR entanglement at the telecommunication wavelength of 1550nm by superimposing a squeezed mode with a vacuum mode. By replacing the vacuum mode with another squeezed mode we then generated 10 dB two-mode squeezed states which were phase-controlled in all degrees of freedom. With these states we implemented a table-top quantum key distribution experiment where the quadratures of Alice's and Bob's homodyne detector were switched randomly. Using 10^8 samples we generated a key which was composably secure in the finite-size regime against collective attacks and demonstrated the possibility of achieving security against coherent attacks.