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Search Publications by: Florent Lecocq (Fed)

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Displaying 1 - 17 of 17

Fabrication and characterization of low-loss Al/Si/Al parallel plate capacitors for superconducting quantum information applications

January 22, 2025
Author(s)
Raymond Simmonds, Sudhir Sahu, Trevyn Larson, Florent Lecocq, Tongyu Zhao, Anthony McFadden
The application of parallel plate capacitors composed of aluminum-contacted, crystalline silicon fins for use in superconducting circuits is explored by evaluating the performance of superconducting lumped element resonators and transmon qubits. High

Systematic Improvements in Transmon Qubit Coherence enabled by Niobium Surface Encapsulation

June 14, 2023
Author(s)
Mustafa BAL, Akshay Murthy, Francesco Crisa, Shaojiang Zhu, Florent Lecocq, Joe Aumentado, Joel Ullom, Pete Hopkins
We present a novel transmon qubit fabrication technique that yields systematic improvements in T1 coherence times. In this study, the devices are fabricated using a novel encapsulation strategy that involves passivating the surface of niobium and thereby

Versatile parametric coupling between two statically decoupled transmon qubits

May 4, 2023
Author(s)
Xiaoyue Jin, Zachary Parrott, SHLOMI KOTLER, Katarina Cicak, Florent Lecocq, John Teufel, Joe Aumentado, Raymond Simmonds
Parametric coupling is a powerful technique for generating tunable interactions between superconducting circuits using only microwave tones. Here, we present a highly flexible parametric coupling scheme demonstrated with two transmon qubits, which can be

Observation of two-mode squeezing in a traveling wave parametric ampli er

April 15, 2022
Author(s)
Florent Lecocq, Jose Aumentado, Martina Esposito, Arpit Ranadive, Luca Planat, Sebastian Leger, Dorian Fraudet, Vincent Jouanny, Olivier Buisson, Wiebke Guichard, Cecile Naud, Nicolas Roch
Traveling wave parametric ampli ers (TWPAs) have recently emerged as essential tools for broadband near quantum-limited ampli cation. However, their use to generate microwave quantum states still misses an experimental demonstration. In this letter, we

Control and readout of a superconducting qubit using a photonic link

March 24, 2021
Author(s)
Florent Lecocq, Franklyn Quinlan, Katarina Cicak, Joe Aumentado, Scott Diddams, John Teufel
Delivering on the revolutionary promise of a universal quantum computer will require processors with millions of quantum bits (qubits). In superconducting quantum processors, each qubit is individually addressed with microwave signal lines that connect

Efficient qubit measurement with a nonreciprocal microwave amplifier

January 13, 2021
Author(s)
Florent Lecocq, Leonardo Ranzani, Gabriel A. Peterson, Katarina Cicak, Xiaoyue Jin, Raymond Simmonds, John Teufel, Jose Aumentado
The act of observing a quantum object fundamentally perturbs its state, resulting in a random walk toward an eigenstate of the measurement operator. Ideally, the measurement is responsible for all dephasing of the quantum state. In practice, imperfections

Microwave measurement beyond the quantum limit with a nonreciprocal amplifier

April 2, 2020
Author(s)
Florent Lecocq, Leonardo Ranzani, Gabriel A. Peterson, Katarina Cicak, Anja Metelmann, Shlomi S. Kotler, Raymond Simmonds, John Teufel, Jose Aumentado
The measurement of a quantum system is often performed by encoding its state in a single observable of a light field. The measurement efficiency of this observable can be reduced by loss or excess noise on the way to the detector. Even a quantum-limited

Demonstration of efficient nonreciprocity in a microwave optomechanical circuit

July 6, 2017
Author(s)
Gabriel A. Peterson, Florent Q. Lecocq, Katarina Cicak, Raymond W. Simmonds, Jose A. Aumentado, John D. Teufel
Abstract The ability to engineer nonreciprocal interactions is an essential tool in modern communication technology as well as a powerful resource for building quantum networks. Aside from large reverse isolation, a nonreciprocal device suitable for

Field Programmable Josephson Amplifier for non-reciprocal microwave signal processing

February 17, 2017
Author(s)
Florent Q. Lecocq, Leonardo Ranzani, Gabriel A. Peterson, Katarina Cicak, Raymond W. Simmonds, John D. Teufel, Jose A. Aumentado
We report on the design and implementation of a Field Programmable Josephson Amplifier (FPJA) - a compact and lossless superconducting circuit that can be programmed in-situ by a set of microwave drives to perform reciprocal and non-reciprocal frequency

Mechanically mediated microwave frequency conversion

January 26, 2016
Author(s)
Florent Q. Lecocq, Jeremy B. Clark, Raymond W. Simmonds, Jose A. Aumentado, John D. Teufel
We report the observation of efficient and low-noise frequency conversion between two microwave modes, mediated by the motion of a mechanical resonator subjected to radiation pressure. We achieve the coherent conversion of more than 10^{12} photons/s with

Quantum Nondemolition Measurement of a Nonclassical State of a Massive Object

December 7, 2015
Author(s)
Florent Q. Lecocq, Jeremy B. Clark, Raymond W. Simmonds, Jose A. Aumentado, John D. Teufel
By coupling a macroscopic mechanical oscillator to two microwave cavities, we simultaneously prepare and monitor a nonclassical steady state of mechanical motion. In each cavity, correlated radiation pressure forces induced by two coherent drives engineer

Overwhelming thermomechanical motion with microwave radiation pressure shot noise

August 21, 2015
Author(s)
John D. Teufel, Florent Q. Lecocq, Raymond W. Simmonds
We measure the fundamental noise processes associated with a continuous linear position measurement of a micromechanical membrane incorporated in a microwave cavity optomechanical circuit. We observe the trade-o ff between the two fundamental sources of

Resolving the vacuum fluctuations of an optomechanical system using an artificial atom

June 15, 2015
Author(s)
Florent Q. Lecocq, John D. Teufel, Jose A. Aumentado, Raymond W. Simmonds
Heisenberg's uncertainty principle results in one of the strangest quantum behaviours: a mechanical oscillator can never truly be at rest. Even at a temperature of absolute zero, its position and momentum are still subject to quantum fluctuations. However

Tunable Resonant and Nonresonant Interactions between a Phase Qubit and LC Resonator

March 26, 2014
Author(s)
Michael S. Allman, Jed D. Whittaker, Manuel C. Castellanos Beltran, Katarina Cicak, Fabio C. Da Silva, Michael DeFeo, Florent Q. Lecocq, Adam J. Sirois, John D. Teufel, Jose A. Aumentado, Raymond W. Simmonds
We use a flux-biased radio frequency superconducting quantum interference device (rf SQUID) with an embedded flux-biased direct current SQUID to generate strong resonant and nonresonant tunable interactions between a phase qubit and a lumped-element
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