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Search Publications by: Emanuel Knill (Fed)

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Displaying 76 - 100 of 182

Asymptotically Optimal Confidences for Rejecting Local Realism

December 22, 2011
Author(s)
Yanbao Zhang, Scott Glancy, Emanuel Knill
Reliable experimental demonstrations of violations of local realism are highly desirable for fundamental tests of Quantum Mechanics. Such violations can be quantified in terms of a confidence for rejecting local realism. We propose a method for computing

Generation and characterization of high-purity, pulsed squeezed light at telecom wavelengths from pp-KTP

November 15, 2011
Author(s)
Thomas Gerrits, Martin J. Stevens, Burm Baek, Brice R. Calkins, Adriana E. Lita, Scott C. Glancy, Emanuel H. Knill, Sae Woo Nam, Richard P. Mirin, Robert Hadfield, Ryan Bennink, Warren Grice, Sander N. Dorenbos, Tony Zijlstra, Teun Klapwijk, Val Zwiller
We characterize a pp-KTP crystal designed to produce pure single mode squeezed vacuum at 1570 nm. Measurements show a raw (corrected) Hong-Ou-Mandel interference with 86 % (90 %) visibility and a circular joint spectral probability distribution with a

Single-qubit-gate error below 10 -4 in a trapped ion

September 14, 2011
Author(s)
Kenton R. Brown, Andrew C. Wilson, Yves Colombe, Christian Ospeklaus, Adam M. Meier, Emanuel H. Knill, Dietrich G. Leibfried, David J. Wineland
In theory, quantum computers can solve certain problems much more efficiently than classical computers [1]. This has motivated experimental efforts to construct and verify devices that manipulate quantum bits (qubits) in a variety of physical systems [2]

Characterization of high-purity, pulsed squeezed light at telecom wavelengths from pp-KTP for quantum information applications

May 1, 2011
Author(s)
Thomas Gerrits, Burm Baek, Martin J. Stevens, Brice R. Calkins, Adriana E. Lita, Scott C. Glancy, Emanuel H. Knill, Sae Woo Nam, Richard P. Mirin, Robert Hadfield, Ryan Bennink, Warren Grice, Sander N. Dorenbos, Tony Zijlstra, Teun Klapwijk, Val Zwiller
We characterize a pp-KTP crystal designed to produce pure single mode squeezed vacuum at 1570 nm. Measurements show Hong-Ou-Mandel interference with 97% visibility and a circular joint spectral distribution with a Schmidt number of 1.08.

Characterization of high-purity, pulsed squeezed light at telecom wavelengths from pp-KTP for quantum information applications

December 1, 2010
Author(s)
Thomas Gerrits, Burm Baek, Martin J. Stevens, Brice R. Calkins, Adriana E. Lita, Scott C. Glancy, Emanuel H. Knill, Sae Woo Nam, Richard P. Mirin, Robert Hadfield, Ryan Bennink, Warren Grice, Sander N. Dorenbos, Tony Zijlstra, Teun Klapwijk, Val Zwiller
Pure optical squeezing in a single mode is highly desirable for quantum information applications such as continuous variable quantum computing and the generation of optical Schrödinger cat states. To generate optical cat states, photons are subtracted from

Generation of optical coherent-state superpositions by number-resolved photon subtraction from the squeezed vacuum

September 9, 2010
Author(s)
Thomas Gerrits, Scott C. Glancy, Tracy S. Clement, Brice R. Calkins, Adriana E. Lita, Aaron Miller, Aaron J. Miller, Alan L. Migdall, Sae Woo Nam, Richard P. Mirin, Emanuel H. Knill
We have created heralded coherent-state superpositions (CSSs) by subtracting up to three photons from a pulse of squeezed vacuum light. To produce such CSSs at a sufficient rate, we used our high-efficiency photon-number-resolving transition edge sensor to

Generation of optical Schrodinger cat states by number-resolved squeezed photon subtraction

July 23, 2010
Author(s)
Thomas Gerrits, Scott C. Glancy, Tracy S. Clement, Brice R. Calkins, Adriana E. Lita, Aaron J. Miller, Alan L. Migdall, Aaron J. Miller, Sae Woo Nam, Richard P. Mirin, Emanuel H. Knill
We have generated and measured an approximation of an optical Schrödinger cat state by photon subtraction from squeezed vacuum. Figure 1 shows the experimental scheme. Photons are probabilistically subtracted from squeezed vacuum and detected with a photon

Fast Quantum Algorithms for Traversing Paths of Eigenstates

May 17, 2010
Author(s)
S. Boixo, Emanuel Knill, Rolando Somma
Consider a path of non-degenerate eigenstates |psi_s>, 0 Solutions to this problem have applications ranging from quantum physics simulation to optimization. For Hamiltonians, the conventional way of doing this is by applying the adiabatic theorem. We give

Quantum Computing

January 28, 2010
Author(s)
Emanuel H. Knill
Imagine a computer that can exploit quantum mechanics to solve previously intractable problems in physics, mathematics and cryptography. Such a quantum computer would revolutionize computing technology while teaching us about fundamental physics and ways

Innovations in Maximum Likelihood Quantum State Tomography

October 9, 2009
Author(s)
Scott C. Glancy, Emanuel H. Knill, Thomas Gerrits, Tracy S. Clement, Brice R. Calkins, Adriana E. Lita, Aaron J. Miller, Alan L. Migdall, Sae Woo Nam, Richard P. Mirin
At NIST we are engaged in an experiment whose goal is to create superpositions of optical coherent states (such superpositions are sometimes called "Schroedinger cat" states). We use homodyne detection to measure the light, and we apply maximum likelihood

Eigenpath Traversal by Phase Randomization

September 1, 2009
Author(s)
S. Boixo, Emanuel Knill, Rolando Somma
A computation in adiabatic quantum computing is achieved by traversing a path of nondegenerate eigenstates of a continuous family of Hamiltonians. We introduce a method that traverses a discretized form of the path: at each step we evolve with the

Generation of optical Schrodinger cat states by number-resolved squeezed photon subtraction

May 31, 2009
Author(s)
Thomas Gerrits, Scott C. Glancy, Tracy S. Clement, Brice R. Calkins, Adriana E. Lita, Aaron J. Miller, Alan L. Migdall, Sae Woo Nam, Richard P. Mirin, Emanuel H. Knill
We have generated and measured an approximation of an optical Schrödinger cat state by photon subtraction from a squeezed state. Using single-photon avalanche photodiode detectors and photon-number-resolving transition edge sensors, we were able to extract