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Displaying 551 - 575 of 871

Flat Frequency Response in the Electronic Measurement of the Boltzmann Constant

June 1, 2013
Author(s)
Jifeng Qu, Horst Rogalla, Yang Fu, Jianqiang Zhang, Alessio Pollarolo, Samuel Benz
A new quantum voltage calibrated Johnson noise thermometer (JNT) was developed at NIM to demonstrate the electrical approach that determines the Boltzmann constant k by comparing electrical and thermal noise power. A measurement with an integration period

Method for Ensuring Accurate AC Waveforms with Programmable Josephson Voltage Standards

June 1, 2013
Author(s)
Charles J. Burroughs, Alain Rufenacht, Samuel Benz, Paul Dresselhaus
The amplitudes of stepwise-approximated sine waves generated by programmable Josephson voltage standards (PJVS) are not intrinsically accurate because the transitions between the quantized voltages depend on numerous conditions. We have developed a method

Testing quantum expanders is co-QMA-complete

May 31, 2013
Author(s)
Yi-Kai Liu, Stephen P. Jordan, Pawel Wocjan, Adam Bookatz
A quantum expander is a unital quantum channel that is rapidly mixing, has only a few Kraus operators, and can be implemented efficiently on a quantum computer. We consider the problem of estimating the mixing time (i.e., the spectral gap) of a quantum

Practical Strategies for QKD Key Production

May 28, 2013
Author(s)
Alan Mink, Anastase Nakassis
We present the quantum key distribution (QKD) secure key ratio expression in a form that exposes the parameters that affect the Reconciliation (error correction) stage. Reconciliation is the least well understood in practical terms and is typically

Frequency Correlated Bi-Photon Spectroscopy using a Tunable Up-Conversion Detector

May 21, 2013
Author(s)
Oliver T. Slattery, Lijun Ma, Paulina S. Kuo, Yong-Su Kim, Xiao Tang
We demonstrated a scheme for frequency correlated bi-photon spectroscopy using a strongly non- degenerate down-conversion source and a tunable up-conversion detector. In this scheme, the spectral function at one wavelength range of a remote object can be

Light-Wave Mixing and Scattering with Quantum Gases

May 21, 2013
Author(s)
Lu Deng, Chengjie Zhu, Edward W. Hagley
We present a general theoretical framework on light-wave mixing and scattering in quantum gases. We show that all such processes that originate from elementary excitations are stimulated Raman or hyper-Raman in nature. In the forward direction, the third

Operation of gamma-ray microcalorimeters at elevated count rates using filters with constraints

May 15, 2013
Author(s)
Bradley K. Alpert, Robert D. Horansky, Douglas A. Bennett, William B. Doriese, Joseph W. Fowler, Andrew Hoover, Michael W. Rabin, Joel N. Ullom
We introduce a filter construction method for pulse processing that differs in two respects from that in standard optimal filtering, in which the average pulse shape and noise power spectral density are combined to create a convolution filter for

Practical implementation of a test of event-based corpuscular model as an alternative to quantum mechanics

May 8, 2013
Author(s)
Sergey V. Polyakov, Alan L. Migdall, Ivo P. Degiovanni, Fabrizio Piacentini, Giorgio Brida, Marco Genovese, Paola Traina
We describe in detail the first experimental test that distinguishes between an event-based corpuscular model of the interaction of photons with matter and quantum mechanics. The test looks at the interference that results as a single photon passes through

Simultaneous Spin-Charge Relaxation in Double Quantum Dots

May 8, 2013
Author(s)
Vanita Srinivasa, Katja C. Nowack, Mohammad Shafiei, Lieven M. Vandersypen, Jacob M. Taylor
We investigate phonon-induced spin and charge relaxation mediated by spin-orbit and hyper- fine interactions for a single electron confined within a double quantum dot. A simple toy model incorporating both direct decay to the ground state of the double

Fast, Optically Controlled Kerr Phase Shifter for Digital Signal Processing

April 18, 2013
Author(s)
Runbing Li, Lu Deng, Edward W. Hagley, Joshua Bienfang, Zachary H. Levine, Marvin G. Payne
We demonstrate an optically controlled Kerr phase shifter using a room-temperature Rb85 vapor operating in a Raman gain scheme. Phase shifts from zero to 𝜋 relative to an unshifted reference wave are observed, and gated operations are demonstrated. We

Bell violation using entangled photons without the fair-sampling assumption

April 14, 2013
Author(s)
Marissa Giustina, Alexandra Mech, Sven Ramelow, Bernhard Wittman, Johannes Keffler, Joern Beyer, Adriana Lita, Thomas Gerrits, Sae Woo Nam, Rupert Ursin, Anton Zeilinger, Brice R. Calkins
The violation of a Bell inequality is an experimental observation that forces the abandonment of a local realistic viewpoint - namely, one in which physical properties are (probabilistically) defined before and independently of measurement, and in which no

Reducing noise in single-photon frequency conversion

April 10, 2013
Author(s)
Paulina S. Kuo, Jason S. Pelc, Oliver T. Slattery, Yong-Su Kim, Martin M. Fejer, Xiao Tang
We demonstrate low-noise and efficient frequency conversion using sum-frequency mixing in a periodically poled LiNbO3 (PPLN) waveguide. Using a 1556 nm pump, 1302 nm photons are efficiently converted to 709 nm photons. We obtain 70% conversion efficiency

Arbitrary waveform generator for quantum information processing with trapped ions

March 20, 2013
Author(s)
Ryan S. Bowler, Ulrich J. Warring, Joseph W. Britton, J. M. Amini
Ions confined in a multi-electrode trap design have been proposed as a possible basis for quantum information processing. This scheme involves transporting ions between spatially distinct locations using time varying electric potentials combined with laser

Highly efficient heralding of entangled single photons

March 11, 2013
Author(s)
Sven Ramelow, Alexandra Mech, Marissa Giustina, Simon Groeblacher, Witlef Wieczorek, Adriana Lita, Brice R. Calkins, Thomas Gerrits, Sae Woo Nam, Anton Zeilinger, Rupert Ursin
Single photons are an important prerequisite for a broad spectrum of quantum optical applications. We experimentally demonstrate a heralded single-photon source based on spontaneous parametric down- conversion in collinear bulk optics, and fiber-coupled

Effect of atomic coherence on "temporal cloaking" in atomic vapors

February 27, 2013
Author(s)
Runbing Li, Lu Deng, Edward W. Hagley, Joshua C. Bienfang, M G. Payne, Mo-Lin Ge
We discuss a different scheme to achieve temporal cloaking in warm atomic vapors. Instead of creating a temporal-spatial window in a patched broadband short optical pulse using static differential dispersion of an optical fiber, we create a temporal

Detecting Single Infrared Photons with 93 % System Efficiency

February 25, 2013
Author(s)
Francesco F. Marsili, Varun B. Verma, Jeffrey A. Stern, Sean D. Harrington, Adriana E. Lita, Thomas Gerrits, Igor Vayshenker, Burm Baek, Matthew D. Shaw, Richard P. Mirin, Sae Woo Nam
Single-photon detectors (SPDs) are nonlinear transducers that respond to the absorption of one or more photons with an electrical signal1. SPDs at near infrared wavelengths with high system detection efficiency (> 90%), low dark count rate (

Radiation-suppressed superconducting quantum bit in a planar geometry

February 19, 2013
Author(s)
Martin O. Sandberg, Tomas A. Ohki, Jose A. Aumentado, Martin P. Weides, David P. Pappas
We present a superconducting transmon qubit circuit design based on large, coplanar capacitor plates and a microstrip resonator. The microstrip geometry, with the ground plane on the back, enhances access to the circuit for state preparation and
Displaying 551 - 575 of 871