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Displaying 301 - 325 of 870

Using Temperature to Reduce Noise in Quantum Frequency Conversion

April 23, 2018
Author(s)
Paulina S. Kuo, Jason S. Pelc, Carsten Langrock, M. M. Fejer
Quantum frequency conversion (QFC) is important in quantum networks to interface nodes operating at different wavelengths and to enable long-distance quantum communication using telecommunications wavelengths. Unfortunately, frequency conversion in actual

Flux-tunable heat sink for quantum electric circuits

April 20, 2018
Author(s)
Matti Partanen, K-Y Tan, S Masuda, Joonas Govenius, Russell Lake, Mate Jenei, Leif Gronberg, Juha Hassel, S Simbierowicz, Visa Vesterinen, J Tuorila, T Ala-Nissila, Mikko Mottonen
Superconducting microwave circuits show great potential for practical quantum technological applications such as quantum information processing. However, fast and on-demand initialization of the quantum degrees of freedom in these devices remains a

Experimentally Generated Random Numbers Certified by the Impossibility of Superluminal Signaling

April 11, 2018
Author(s)
Peter L. Bierhorst, Emanuel H. Knill, Scott C. Glancy, Yanbao Zhang, Alan Mink, Stephen P. Jordan, Andrea Rommal, Yi-Kai Liu, Bradley Christensen, Sae Woo Nam, Martin J. Stevens, Lynden K. Shalm
From dice to modern complex circuits, there have been many attempts to build increasingly better devices to generate random numbers. Today, randomness is fundamental to security and cryptographic systems, as well as safeguarding privacy. A key challenge

Effects of resonant-laser excitation on the emission properties in a single quantum dot

March 27, 2018
Author(s)
Sergey Polyakov, Vivien Loo, Edward Flagg, Glenn S. Solomon, Olivier Gazzano, Tobias Huber
While many solid-state emitters can be optically excited non-resonantly, resonant excitation is necessary for many quantum information protocols as it often maximizes the non-classicality of the emitted light. Here, we study the resonance fluorescence in a

Quantifying the post-quantum security-margin of popular block ciphers

March 27, 2018
Author(s)
Yi-Kai Liu, Brittanney Amento-Adelmann, Markus Grassl, Brandon Langenberg, Eddie Schoute, Rainer Steinwandt
Mounting an exhaustive key search against a block cipher with Grover's algorithm requires the implementation of the target cipher on a quantum computer. We report quantum circuits and resource bounds for various block ciphers with different design

Local Randomness: Examples and Application

March 19, 2018
Author(s)
Honghao Fu, Carl Miller
When two players achieve a superclassical score at a nonlocal game, their outputs must contain intrinsic randomness. This fact has many useful implications for quantum cryptography. Recently it has been observed (C. Miller, Y. Shi, Quant. Inf. & Comp. 17

Quantum receiver for large alphabet communication

February 21, 2018
Author(s)
Sergey Polyakov, Ivan Burenkov, Olga Tikhonova
Quantum mechanics allows measurements that surpass the fundamental sensitivity limits of classical methods. To benefit from the quantum advantage in a practical setting, the receiver should use communication channel resources optimally; this can be done

Dark state optical lattice with sub-wavelength spatial structure

February 20, 2018
Author(s)
Sarthak Subhankar, Tsz-Chun Tsui, James V. Porto, Steve Rolston, Przemek Bienias, Alexey Gorshkov, Mateusz Lacki, Michael Baranov, Peter Zoller
We report on the experimental realization of a conservative optical lattice for cold atoms with sub-wavelength spatial structure. The potential is based on the nonlinear optical response of three- level atoms in laser-dressed dark states, which is not

Diffusion Monte Carlo versus adiabatic computation for local Hamiltonians

February 15, 2018
Author(s)
Stephen P. Jordan, Jacob Bringewatt, Alan Mink, William Dorland
Most research regarding quantum adiabatic optimization has focused on stoquastic Hamiltonians, whose ground states can be expressed with only real, nonnegative amplitudes. This raises the question of whether classical Monte Carlo algorithms can efficiently

Increased interference fringe visibility from the post fabrication heat treatment of a perfect crystal silicon neutron interferometer

February 8, 2018
Author(s)
Michael G. Huber, Muhammad D. Arif, Thomas H. Gnaupel-Herold, Michelle E. Jamer, Ben Heacock, David G. Cory, R. Haun, Joachim Nsofini, Dimitry A. Pushin, Ivar Taminiau, A.R. Young
We find that annealing a previously chemically etched interferometer at 800 °C dramatically increased the interference fringe visibility from 23 % to 90 %. The Bragg plane misalignments were also measured before and after annealing using neutron rocking

Keyring models: An Approach to Steerability

February 6, 2018
Author(s)
Carl A. Miller, Roger Colbeck, Yaoyun Shi
If a measurement is made on one half of a bipartite system then, conditioned on the outcome, the other half achieves a new reduced state. If these reduced states defy classical explanation -- that is, if shared randomness cannot produce these reduced

STM patterned nanowire measurements using photolithographically defined implants in Si(100)

January 29, 2018
Author(s)
Aruna N. Ramanayaka, Hyun Soo Kim, Ke Tang, Xiqiao Wang, Richard M. Silver, Michael D. Stewart, Joshua M. Pomeroy
Using photolithographically defined implant wires for electrical connections, we demonstrate measurement of a scanning tunneling microscope (STM) patterned nanoscale electronic device on Si(100), eliminating the onerous alignment procedures and electron

Thermodynamic Analysis of Classical and Quantum Search Algorithms

January 19, 2018
Author(s)
Ray A. Perlner, Yi-Kai Liu
We analyze the performance of classical and quantum search algorithms from a thermodynamic perspective, focusing on resources such as time, energy, and memory size. We consider two examples that are relevant to post-quantum cryptography: Grover's search

Superconducting micro-resonator arrays with ideal frequency spacing

December 20, 2017
Author(s)
Xiangliang Liu, Weijie Guo, Y Wang, M Dai, L F. Wei , Bradley J. Dober, Christopher M. McKenney, Gene C. Hilton, Johannes Hubmayr, Jason E. Austermann, Joel Ullom, Jiansong Gao, Michael Vissers
We present a wafer trimming technique for producing superconducting micro-resonator arrays with highly uniform frequency spacing. With the light-emitting diode mapper technique demonstrated previously, we first map the measured resonance frequencies to the

Polar Codes for Quantum Key Distribution

December 14, 2017
Author(s)
Anastase Nakassis
This paper addresses the performance of polar codes in the context of the quantum key distribution (QKD) protocol. It introduces the notion of an interactive polar decoder and studies its performance. The results demonstrate that the interactive decoder is

Rydberg Atom Electric-Field Metrology

November 28, 2017
Author(s)
Joshua A. Gordon, Christopher L. Holloway, Matthew T. Simons
We present a technique which shows great promise for realizing an atomic standard measurement of RF fields that is intrinsically calibrated, directly linked to the SI and atomic structural constants. This technique relies on the reponse of Rydberg atoms to

Simultaneous, Full Characterization of a Single-Photon State

November 15, 2017
Author(s)
Tim O. Thomay, Sergey Polyakov, Elizabeth A. Goldschmidt, Glenn S. Solomon, Olivier Gazzano, Vivien Loo
As single-photon sources become more mature and are used more often in quantum information, communications, and measurement applications, their characterization becomes more important. Single-photon-like light is often characterized by its brightness, as

Valley blockade in a silicon double quantum dot

November 13, 2017
Author(s)
Justin K. Perron, Michael Gullans, Jacob Taylor, Michael Stewart, Neil M. Zimmerman
Electrical transport in double quantum dots (DQD) is useful for illuminating many interesting aspects of the carrier states in quantum dots. Here we show data comparing bias triangles (i.e., regions of allowed current in DQDs) at positive and negative bias

Flux-tunable phase shifter for microwaves

November 7, 2017
Author(s)
Roope J. Kokkoniemi, Tuomas Ollikainen, Sakari Saarenpaa, Janne Kokkala, Ceren Dag, Mikko Mottonen, Russell Lake
We introduce a magnetic-flux-tunable phase shifter for propagating microwave photons, based on three equidistant superconducting quantum interference devices (SQUIDs) on a transmission line. We experimentally implement the phase shifter and demonstrate

Quantum Estimation of the Classical Gravitational Field

November 6, 2017
Author(s)
Emanuel H. Knill, T. G. Downes, G. J. Milburn, C. M. Caves, J. R. van Meter
Here we describe a quantum limit to measurement of the classical gravitational field. Specifically, we formulate the quantum Cramer-Rao lower bound for estimating the single parameter in any one- parameter family of spacetime metrics. We employ the locally

Rigidity of the magic pentagram game

November 2, 2017
Author(s)
Amir Kalev, Carl Miller
A game is rigid if a near-optimal score guarantees, under the sole assumption of the validity of quantum mechanics, that the players are using an approximately unique quantum strategy. As such, rigidity has a vital role in quantum cryptography as it
Displaying 301 - 325 of 870