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Search Publications by: Emanuel Knill (Fed)

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Displaying 51 - 75 of 164

Randomized Benchmarking of Multiqubit Gates

June 29, 2012
Author(s)
John P. Gaebler, Adam M. Meier, Ting Rei Tan, Ryan S. Bowler, Yiheng Lin, David Hanneke, John D. Jost, Jonathan Home, Emanuel H. Knill, Dietrich G. Leibfried, David J. Wineland
As experimental platforms for quantum information processing continue to mature, characterization of the quality of unitary gates that can be applied to their quantum bits (qubits) becomes essential. Eventually, the quality must be sufficiently high to

The non-Abelian Duality Problem

June 6, 2012
Author(s)
Emanuel H. Knill, E. Cobanera, Gerardo Ortiz
We exploit a new theory of duality transformations to construct dual representations of models incompatible with traditional duality transformations. Hence we obtain a solution to the long-standing problem of non-Abelian dualities that hinges on two key

Magic-state distillation with the four-qubit code

April 20, 2012
Author(s)
Adam M. Meier, Bryan K. Eastin, Emanuel H. Knill
The distillation of magic states is an often-cited technique for enabling universal quantum computing once the error rate for a special subset of gates has been made negligible by other means. We present a routine for magic-state distillation that reduces

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