Horace P. Yuen

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Strengthening a result of Yuen-Kennedy-Lax and Holevo (YKLH), we relax the (redundant) standard conditions for optimality of minimum-error quantum measurements while retaining sufficiency. This result is made robust by giving quantitative bounds on non-optimality when the simplified conditions fail to hold. These conditions serendipitously appeared as an(More)
The classical-information capacity of lossy bosonic channels is studied, with emphasis on the far-field free space channel. 1 Classical capacity A prominent landmark in the extension of Shannon information theory to the quantum domain is the realization that any particular physical system can store only a finite amount of information. As a consequence, the(More)
A team of researchers from the Massachusetts Institute of Technology (MIT) and Northwestern University (NU) is developing a system for long-distance, high- delity qubit tele-portation. Such a system will be required if future quantum computers are to be linked together into a quantum Internet. This paper presents recent progress that the MIT/NU team has(More)
We demonstrate high data-rate quantum-noise{protected data encryption through optical fibers using coherent states of light. Specifically, we demonstrate 650Mbps data encryption through a 10Gbps data-bearing, in-line amplified 200km-long line. In our protocol, legitimate users (who share a short secret-key) communicate using an M-ry signal set while an(More)