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We present a tuneup protocol for qubit gates with tenfold speedup over traditional methods reliant on qubit initialization by energy relaxation. This speedup is achieved by constructing a cost function for Nelder-Mead optimization from real-time correlation of nondemolition measurements interleaving gate operations without pause. Applying the protocol on a transmon qubit achieves 0.999 average Clifford fidelity in one minute, as independently verified using randomized benchmarking and gate-set tomography. The adjustable sensitivity of the cost function allows the detection of fractional changes in the gate error with a nearly constant signal-to-noise ratio. The restless concept demonstrated can be readily extended to the tuneup of two-qubit gates and measurement operations.
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We present a tuneup protocol for qubit gates with tenfold speedup over traditional methods reliant on qubit initialization by energy relaxation. This speedup is achieved by constructing a cost function for Nelder-Mead optimization from real-time correlation of nondemolition measurements interleaving gate operations without pause. Applying the protocol on a transmon qubit achieves 0.999 average Clifford fidelity in one minute, as independently verified using randomized benchmarking and gate-set tomography. The adjustable sensitivity of the cost function allows the detection of fractional changes in the gate error with a nearly constant signal-to-noise ratio. The restless concept demonstrated can be readily extended to the tuneup of two-qubit gates and measurement operations.
Journal article(2016)
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RJ Bolt, D Cavallo, G Gerini, D Deurloo, G Grooters, A Neto, G Toso
In this paper, we present the characterization of a Ku-band connected-dipole array for mobile Satcom application. The prototype array consists of 2×256 dipole radiators arranged in a square grid, to form 16×16 dual-polarized cells. It has been designed to operate over a wideband ranging from 10.7 to 14.5 GHz (30%), accommodating in a single antenna both the transmit (14.0 to 14.5 GHz) and the receive (10.70 to 12.75 GHz) bands for the application. The array has been characterized in terms of active reflection (AR) and radiation patterns. Dedicated test support equipment (TSE) has been developed and used to test the array radiation characteristics. Over the frequency range of operation, the array maintains good matching (ensuring system gain to noise temperature better than 8 dB/K) and good radiation performance while scanning as far as 60 degrees in all the azimuth planes. The cross-polarization suppression is better than 15 dB within most of the scan range and reaches 10 dB for the extreme scan angles in the diagonal plane.
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In this paper, we present the characterization of a Ku-band connected-dipole array for mobile Satcom application. The prototype array consists of 2×256 dipole radiators arranged in a square grid, to form 16×16 dual-polarized cells. It has been designed to operate over a wideband ranging from 10.7 to 14.5 GHz (30%), accommodating in a single antenna both the transmit (14.0 to 14.5 GHz) and the receive (10.70 to 12.75 GHz) bands for the application. The array has been characterized in terms of active reflection (AR) and radiation patterns. Dedicated test support equipment (TSE) has been developed and used to test the array radiation characteristics. Over the frequency range of operation, the array maintains good matching (ensuring system gain to noise temperature better than 8 dB/K) and good radiation performance while scanning as far as 60 degrees in all the azimuth planes. The cross-polarization suppression is better than 15 dB within most of the scan range and reaches 10 dB for the extreme scan angles in the diagonal plane.
Conference paper(2012)
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D. Cavallo, G. Gerini, R Bolt, R Grooters, D. Deurloo, A. Neto, B. van Zalk, G Toso, R. Midthassel
This work reports on the development and performance of a doubly-polarized array of connected dipoles for in-flight entertainment. The array is designed to simultaneously operate in the uplink and the downlink bands, with an overall bandwidth of about 30%, from 10.7 to 14.5 GHz. The array prototype comprises 16×16 elements in each polarization for a total of 512 elements. The use of a loop-shaped transformer in the feed lines and a wide angle impedance matching (WAIM) sheet allows to achieve low cross-polarization and sufficiently good matching for scanning up to ±60° in elevation for every azimuth plane.
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This work reports on the development and performance of a doubly-polarized array of connected dipoles for in-flight entertainment. The array is designed to simultaneously operate in the uplink and the downlink bands, with an overall bandwidth of about 30%, from 10.7 to 14.5 GHz. The array prototype comprises 16×16 elements in each polarization for a total of 512 elements. The use of a loop-shaped transformer in the feed lines and a wide angle impedance matching (WAIM) sheet allows to achieve low cross-polarization and sufficiently good matching for scanning up to ±60° in elevation for every azimuth plane.