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Search Publications by: Varun Verma (Fed)

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Displaying 76 - 100 of 147

A quantum enigma machine: Experimentally demonstrating quantum data locking

August 12, 2016
Author(s)
Daniel Lum, Michael S. Allman, Thomas Gerrits, Cosmo Lupo, Seth Lloyd, Varun Verma, Sae Woo Nam, John Howell
During the first half of the 20th century, enigma machines (i.e., pseudorandom polyalphabetic ciphers) of increasing sophistication gave better resistance against brute-force codebreaking attacks. However, the ultimate form of cryptographic security is

Demonstration of EPR steering using single-photon path entanglement and displacement-based detection

August 12, 2016
Author(s)
T Guerreiro, F. Monteiro, A Martin, J B. Brask, T Vertesi, Boris Korzh, Felix Bussieres, Varun Verma, Adriana Lita, Richard Mirin, Sae Woo Nam, Francesco Marsili, Matthew D. Shaw, Nicolas Gisin, Nicolas Brunner, Hugo Zbinden, Robert Thew
We demonstrate the violation of an EPR steering inequality developed for single photon path entanglement with displacement-based detection. We use a high-rate source of heralded single-photon path-entangled states, combined with high efficiency

Experimental investigation of the detection mechanism in WSi nanowire superconducting single photon detectors

July 18, 2016
Author(s)
Rosalinda Gaudio, Jelmer J. Renema, Zili Zhou, Varun Verma, Jeff Shainline, Martin Stevens, Richard Mirin, Sae Woo Nam, Martin P. van Exter, Michiel J. de Dood, Andrea Fiore
We use quantum detector tomography to investigate the detection mechanism in WSi nanowire superconducting single photon detectors (SSPDs). To this purpose, we fabricated a 250 nm wide and 250 nm long WSi nanowire and measured its response to impinging

Athermal avalanche in bilayer superconducting nanowire single-photon detectors

March 28, 2016
Author(s)
Varun B. Verma, Martin J. Stevens, Richard P. Mirin, Sae Woo Nam
We demonstrate that two superconducting nanowires separated by a thin insulating barrier can undergo a thermal avalanche process. In this process, Joule heating caused by a photodetection event in one nanowire and the associated production of athermal

Hotspot Relaxation Dynamics in a Current Carrying Superconductor

March 17, 2016
Author(s)
Francesco Marsili, Martin Stevens, Alex Kozorezov, Varun Verma, Colin Lambert, Jeffrey A. Stern, Rob Horansky, Shellee D. Dyer, Shannon Duff, David P. Pappas, Matthew Shaw, Richard Mirin, Sae Woo Nam
When a photon is absorbed in a superconductor it creates a region of nonequilibrium superconductivity referred to as a hotspot [1]. The operation of most superconducting single photon detectors (microwave kinetic inductance detectors, MKIDs [2,3]

High-efficiency superconducting nanowire single-photon detectors fabricated from MoSi thin-films

December 22, 2015
Author(s)
Varun B. Verma, Boris Korzh, Felix Bussieres, Robert D. Horansky, Shellee D. Dyer, Adriana E. Lita, Igor Vayshenker, Francesco Marsili, Matthew D. Shaw, Hugo Zbinden, Richard P. Mirin, Sae Woo Nam
We report on MoSi SNSPDs which achieved high system detection efficiency (87.1 ± 0.5% at 1542 nm) at 0.7 K and we demonstrate that these detectors can also be operated with saturated internal efficiency at a temperature of 2.3 K in a Gifford-McMahon

A strong loophole-free test of local realism

December 16, 2015
Author(s)
Lynden K. Shalm, Evan Meyer-Scott, B. G. Christensen, Peter L. Bierhorst, Michael A. Wayne, Deny Hamel, Martin J. Stevens, Thomas Gerrits, Scott C. Glancy, Michael S. Allman, Kevin J. Coakley, Shellee D. Dyer, Adriana E. Lita, Varun B. Verma, Joshua C. Bienfang, Alan L. Migdall, Yanbao Zhang, William Farr, Francesco Marsili, Matthew D. Shaw, Jeffrey Stern, Carlos Abellan, Waldimar Amaya, Valerio Pruneri, Thomas Jennewein, Morgan Mitchell, P. G. Kwiat, Richard P. Mirin, Emanuel H. Knill, Sae Woo Nam
We present a loophole-free violation of local realism using entangled photon pairs. We ensure that all relevant events in our Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high

Quasiparticle recombination in hotspots in superconducting current-carrying nanowires

August 6, 2015
Author(s)
Alex Kozorezov, Colin Lambert, Francesco Marsili, Martin Stevens, Varun Verma, Jeffrey A. Stern, Rob Horansky, Shellee D. Dyer, Shannon Duff, David P. Pappas, Adriana Lita, Matthew D. Shaw, Richard Mirin, Sae Woo Nam
We describe a kinetic model of recombination of nonequilibrium quasiparticles generated by single photon absorption in superconducting current-carrying nanowires. The model is developed to interpret two-photon detection experiments in which a single photon

A near-infrared 64-pixel superconducting nanowire single photon detector array with integrated multiplexed readout

May 14, 2015
Author(s)
Michael S. Allman, Varun B. Verma, Martin J. Stevens, Thomas Gerrits, Robert D. Horansky, Adriana E. Lita, Francesco Marsili, A. Beyer, Matthew Shaw, D. Kumor, Richard P. Mirin, Sae Woo Nam
We demonstrate a 64-pixel free-space-coupled array of superconducting nanowire single photon detectors optimized for high detection efficiency in the near-infrared range. An integrated, readily scalable, multiplexed readout scheme is employed to reduce the