Fast and High-Fidelity Entangling Gate through Parametrically Modulated Longitudinal Coupling

We investigate an approach to universal quantum computation based on the modulation of longitudinal qubit-oscillator coupling. We show how to realize a controlled-phase gate by simultaneously modulating the longitudinal coupling of two qubits to a common oscillator mode. In contrast to the more familiar transversal qubit-oscillator coupling, the magnitude of the effective qubit-qubit interaction does not rely on a small perturbative parameter. As a result, this effective interaction strength can be made large, leading to short gate times and high gate fidelities. We moreover show how the gate infidelity can be exponentially suppressed with squeezing and how the entangling gate can be generalized to qubits coupled to separate oscillators. Our proposal can be realized in multiple physical platforms for quantum computing, including superconducting and spin qubits.Comment: 5 pages, 3 figures, Supplemental Materia

Unmanned systems interoperability standards

Over the past several years, there has been rapid growth in the development and employment of unmanned systems in military and civilian endeavors. Some military organizations have expressed concern that these systems are being fielded without sufficient capabilities to interoperate with existing systems. Despite recognition of this requirement, interoperability efforts remain diverse and disjointed across the United States and internationally. The Naval Postgraduate School (NPS), Monterey, California, was sponsored by the U.S. Office of the Secretary of Defense (OSD) Joint Ground Robotics Enterprise (JGRE) in Fiscal Year 2016 (FY16) to explore (1) enhancement of robotics education; (2) improved representation of robotic systems in combat simulations; and (3) interoperability standards for military robotics systems. This report discusses work performed in FY16 to identify current and emerging interoperability standards for unmanned systems, including interactions of robotic systems with command and control (C2) and simulation systems. The investigation included assessment of the applicability of standardization activities in the Simulation Interoperability Standards Organization (SISO) in its development of the Phase 1 Coalition Battle Management Language (C-BML) and currently in-progress Command and Control Systems - Simulation Systems Interoperation (C2SIM) standardization efforts. The report provides a recommended approach, standards, activities, and timetable for a cross-system communications roadmap.Secretary of Defense Joint Ground Robotics Enterprise, 3090 Defense Pentagon, Room 5C756, Washington, DC 20301Office of the Secretary of Defense Joint Ground Robotics Enterprise.Approved for public release; distribution is unlimited

Learning circuits with few negations

Monotone Boolean functions, and the monotone Boolean circuits that compute them, have been intensively studied in complexity theory. In this paper we study the structure of Boolean functions in terms of the minimum number of negations in any circuit computing them, a complexity measure that interpolates between monotone functions and the class of all functions. We study this generalization of monotonicity from the vantage point of learning theory, giving near-matching upper and lower bounds on the uniform-distribution learnability of circuits in terms of the number of negations they contain. Our upper bounds are based on a new structural characterization of negation-limited circuits that extends a classical result of A. A. Markov. Our lower bounds, which employ Fourier-analytic tools from hardness amplification, give new results even for circuits with no negations (i.e. monotone functions)