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Search Publications

NIST Authors in Bold

Displaying 276 - 300 of 868

Spin decoherence in a two-qubit CPHASE gate: the critical role of tunneling noise

November 27, 2018
Author(s)
Peihao Huang, Neil M. Zimmerman, Garnett W. Bryant
The rapid progress in the manipulation and detection of semiconductor spin qubits enables the experimental demonstration of a high fidelity two-qubit logic gate, which is necessary for universal quantum computing. Here, we study the decoherence of two

Spin relaxation of a donor electron coupled to interface states

November 16, 2018
Author(s)
Peihao Huang, Garnett W. Bryant
An electron spin qubit in a silicon donor atom is a promising candidate for quantum information processing because of its long coherence time. To be sensed with a single-electron transistor, the donor atom is usually located near an interface, where the

The Complexity and Verification of Quantum Random Circuit Sampling

October 29, 2018
Author(s)
Adam Bouland, William J. Fefferman, Chinmay Nirkhe, Umesh Vazirani
A critical milestone on the path to useful quantum computers is the demonstration of a quantum computation that is prohibitively hard for classical computers -- a task referred to as quantum supremacy. A leading near-term candidate is sampling from the

Recovering quantum gates from few average gate fidelities

October 24, 2018
Author(s)
Yi-Kai Liu, Ingo Roth, Richard Kueng, Shelby Kimmel, David Gross, Jens Eisert, Martin Kliesch
Characterizing quantum processes is a key task in and constitutes a challenge for the development of quantum technologies, especially at the noisy intermediate scale of today's devices. One method for characterizing processes is randomized benchmarking

On the scalability of parametric down-conversion for generating higher-order Fock states

October 18, 2018
Author(s)
Thomas Gerrits, Adriana Lita, Sae Woo Nam, Johannes Tiedau, Tim J. Bartley, Georg Harder, Christine Silberhorn
Spontaneous parametric down-conversion (SPDC) is the most widely-used method to generate higher-order Fock states (n>2). Yet, a consistent performance analysis from fundamental principles is missing. Here we address this problem by analyzing state fidelity

Joint Quantum State and Measurement Tomography with Incomplete Measurements

October 12, 2018
Author(s)
Adam C. Keith, Charles H. Baldwin, Scott C. Glancy, Emanuel H. Knill
Estimation of quantum states and measurements is crucial for the implementation of quantum information protocols. The standard method for each is quantum tomography (QT). However, QT suffers from systematic errors caused by imperfect knowledge of the

Randomness Extraction from Bell Violation with Continuous Parametric Down-Conversion

October 9, 2018
Author(s)
Thomas Gerrits, Sae Woo Nam, Adriana Lita, Lijiong Shen, Jianwei Lee, Le Phuc Thinh, Jean-Daniel Bancal, Alessandro Cere
We present a violation of the CHSH inequality without the fair sampling assumption with a continuously pumped photon pairs source combined with two high efficiency superconducting detectors. Due to the continuous nature of the source, the choice of the

Quadrature Histograms in Maximum Likelihood Quantum State Tomography

August 22, 2018
Author(s)
Leonardo E. Silva, Scott Glancy, Hilma H. Macedo De Vasconcelos
Quantum state tomography aims to determine the quantum state of a system from measured data and is an essential tool for quantum information science. When dealing with continuous variable quantum states of light, tomography is often done by measuring the

Pseudorandom Quantum States

August 19, 2018
Author(s)
Yi-Kai Liu, Zhengfeng Ji, Fang Song
We propose the concept of pseudorandom quantum states, which appear random to any quantum polynomial-time adversary. It offers a computational approximation to perfectly random quantum states (analogous to cryptographic pseudorandom generators), as opposed

Readout architectures for superconducting nanowire single photon detectors

August 16, 2018
Author(s)
Adam N. McCaughan
Advances in the development of superconducting nanowire single photon detectors (SNSPD) have guaranteed that they remain a leading photon detection technology in applications such as quantum information, low-power optical communications, and the life

Towards superconductivity in p-type delta-doped Si/Al/Si heterostructures

July 30, 2018
Author(s)
Aruna N. Ramanayaka, Hyun Soo Kim, Joseph A. Hagmann, Roy E. Murray, Ke Tang, Neil M. Zimmerman, Curt A. Richter, Joshua M. Pomeroy, Frederick Meisenkothen, Huairuo Zhang, Albert Davydov, Leonid A. Bendersky
In pursuit of superconductivity in p-type silicon (Si), we are using a single atomic layer of aluminum (Al) sandwiched between a Si substrate and a thin Si epi-layer. The delta layer was fabricated starting from an ultra high vacuum (UHV) flash anneal of

Measurement of Leakage Current to Ground in Programmable Josephson Voltage Standard

July 8, 2018
Author(s)
Alain Rufenacht, Charles J. Burroughs, Paul D. Dresselhaus, Samuel P. Benz
The voltage error associated with the leakage current of programmable Josephson voltage standards (PJVS) is one of the largest contributions to the uncertainty in direct comparison of voltage standards. Due to the parallel biasing scheme of the PJVS and

Faster quantum algorithm to simulate Fermionic quantum field theory

July 1, 2018
Author(s)
Ali Hamed Moosavian, Stephen P. Jordan
In quantum algorithms discovered so far for simulating scattering processes in quantum field theories, state preparation is the slowest step. We present a new algorithm for preparing particle states to use in simulation of Fermionic Quantum Field Theory

Using Temperature to Reduce Noise in Quantum Frequency Conversion

May 12, 2018
Author(s)
Paulina Kuo, Jason S. Pelc, Carsten Langrock, M. M. Fejer
A main source of noise in quantum frequency conversion is spontaneous Raman scattering, which can be reduced by lowering the operating temperature. We show reduction in dark count rates that agrees well with theory.

Noise Reduction in Optically Controlled Quantum Memory

May 7, 2018
Author(s)
Lijun Ma, Oliver T. Slattery, Xiao Tang
Quantum memory is an essential device for quantum communications systems and quantum computers. An important category of quantum memory, called Optically controlled quantum memory, uses a strong classical beam to control the storage and re-emission of a

Enhanced superconducting transition temperature in electroplated rhenium

April 30, 2018
Author(s)
David P. Pappas, Don David, Mustafa Bal, Ilke Arslan, Paul T. Blanchard, Ronald B. Goldfarb, Dustin A. Hite, Hsiang S. Ku, Russell E. Lake, Junling Long, Alexana Roshko, Lee D. Pappas, Britton L. Plourde, Jianguo Wen, Xian Wu, Corey Rae H. McRae
We show that electroplated Re films in multilayers with noble metals such as Cu, Au, and Pd have an enhanced superconducting critical temperature relative to previous methods of preparing Re. The dc resistance and magnetic susceptibility indicate a critical

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
Displaying 276 - 300 of 868