National Technology & Engineering Solutions of Sandia, LLC

Sandia Corporation

Mohan Sarovar

Ryan Camacho

Daniel B S Soh

Anthony L Lentine

Christopher Todd DeRose

Paul Davids

David Aaron Farley

Kenneth Michael Rudinger

Alicia Bette Magann

Constantin Brif

Matthew Grace

A system for identifying approximate solutions to discrete optimization problems includes a quantum computing device. The quantum computing device iteratively configures a layered quantum circuit to evaluate a Hamiltonian representation of a cost function over a set of parameter values. After each iteration, the quantum computing device identifies a new parameter value based upon an estimate of an expectation value under the quantum state output by execution of the layered quantum circuit. The quantum computing device updates a configuration of the layered quantum circuit based upon the new parameter value. After a final iteration, the output quantum state of the layered quantum circuit is measured to identify an approximate solution vector. This solution vector is output as optimization results that are indicative of an approximate solution to the discrete optimization problem.

Feedback-based quantum optimization

Described herein are various technologies pertaining to detecting tampering of a seal based upon quantum optical communication via a communications channel comprising the seal. A plurality of pulses of light encoded with random data are transmitted on the communications channel, whereupon they are received and their data values measured. The measured data values of the pulses are then compared to the known transmitted data to determine a correlation statistic between the transmitted and received data values. Tampering with the seal can be detected based upon identifying that the correlation statistic has dropped below a threshold non-tampered level of correlation between transmitted and received values.

Secure fiber optic seals enabled by quantum optical communication concepts

Various technologies for performing continuous-variable (CV) and discrete-variable (DV) quantum key distribution (QKD) with integrated electro-optical circuits are described herein. An integrated DV-QKD system uses Mach-Zehnder modulators to modulate a polarization of photons at a transmitter and select a photon polarization measurement basis at a receiver. An integrated CV-QKD system uses wavelength division multiplexing to send and receive amplitude-modulated and phase-modulated optical signals with a local oscillator signal while maintaining phase coherence between the modulated signals and the local oscillator signal.

Transceivers and receivers for quantum key distribution and methods pertaining thereto

Various technologies for continuous-variable quantum key distribution without transmitting a transmitter's local oscillator are described herein. A receiver on an optical transmission channel uses an oscillator signal generated by a light source at the receiver's location to perform interferometric detection on received signals. An optical reference pulse is sent by the transmitter on the transmission channel and the receiver computes a phase offset of the transmission based on quadrature measurements of the reference pulse. The receiver can then compensate for the phase offset between the transmitter's reference and the receiver's reference when measuring quadratures of received data pulses.

Self-referenced continuous-variable quantum key distribution

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Albany, CA, United States of America

Mohan Sarovar