Joshua Combes
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View article: Quantum-enhanced multiparameter sensing in a single mode
Quantum-enhanced multiparameter sensing in a single mode Open
Precise measurements underpin scientific and technological advancements. Quantum mechanics provides an avenue to enhance precision, but it comes with a restriction: Incompatible observables, such as position and momentum, cannot be simulta…
View article: Noise constraints on sensitivity scaling in super-Heisenberg quantum metrology
Noise constraints on sensitivity scaling in super-Heisenberg quantum metrology Open
Quantum-enhanced metrology surpasses classical metrology by improving estimation precision scaling with a resource $N$ (e.g., particle number or energy) from $1/\sqrt{N}$ to $1/N$. Through the use of nonlinear effects, Roy and Braunstein~\…
View article: Quantum-Enhanced Multi-Parameter Sensing in a Single Mode
Quantum-Enhanced Multi-Parameter Sensing in a Single Mode Open
Precision metrology underpins scientific and technological advancements. Quantum metrology offers a pathway to surpass classical sensing limits by leveraging quantum states and measurement strategies. However, measuring multiple incompatib…
View article: Quantum permutation puzzles with indistinguishable particles
Quantum permutation puzzles with indistinguishable particles Open
Permutation puzzles, such as the Rubik's Cube and the 15 puzzle, are enjoyed by the general public and mathematicians alike. Here we introduce quantum versions of permutation puzzles where the pieces of the puzzles are replaced with indist…
View article: Enumeration of all superconducting circuits up to 5 nodes
Enumeration of all superconducting circuits up to 5 nodes Open
Nonlinear superconducting circuits can be used as amplifiers, transducers, and qubits. Only a handful of superconducting circuits have been analyzed or built, so many high-performing configurations likely remain undiscovered. We seek to ca…
View article: Squeezed dual-comb spectroscopy
Squeezed dual-comb spectroscopy Open
Laser spectroscopy and interferometry have provided an unparalleled view into the fundamental nature of matter and the universe through ultra-precise measurements of atomic transition frequencies and gravitational waves. Optical frequency …
View article: Precisely determining photon-number in real time
Precisely determining photon-number in real time Open
Superconducting transition-edge sensors (TES) are extremely sensitive microcalorimeters used as photon detectors with unparalleled energy resolution. They have found application from measuring astronomical spectra through to determining th…
View article: Quantum theory of temporally mismatched homodyne measurements with applications to optical-frequency-comb metrology
Quantum theory of temporally mismatched homodyne measurements with applications to optical-frequency-comb metrology Open
The fields of precision timekeeping and spectroscopy increasingly rely on\noptical frequency comb interferometry. However, comb-based measurements are not\ndescribed by existing quantum theory because they exhibit both large mode\nmismatch…
View article: The performance of random bosonic rotation codes
The performance of random bosonic rotation codes Open
Bosonic error correcting codes utilize the infinite dimensional Hilbert space of a harmonic oscillator to encode a qubit. Bosonic rotation codes are characterized by a discrete rotation symmetry in their Wigner functions and include codes …
View article: Explicit error-correction scheme and code distance for bosonic codes with rotational symmetry
Explicit error-correction scheme and code distance for bosonic codes with rotational symmetry Open
Bosonic codes with rotational symmetry are currently one of the best performing quantum error correcting codes. Little is known about error propagation and code distance for these rotation codes in contrast with qubit codes and Bosonic cod…
View article: Sub-universal variational circuits for combinatorial optimization problems
Sub-universal variational circuits for combinatorial optimization problems Open
Quantum variational circuits have gained significant attention due to their applications in the quantum approximate optimization algorithm and quantum machine learning research. This work introduces a novel class of classical probabilistic…
View article: Table of Contents
Table of Contents Open
As the official means of communication for the IEEE Control Systems Society, IEEE Control Systems publishes interesting, useful, and informative material on all aspects of control system technology for the benefit of control educators, pra…
View article: Nonlinear Sideband Cooling to a Cat State of Motion
Nonlinear Sideband Cooling to a Cat State of Motion Open
The ability to prepare a macroscopic mechanical resonator into a quantum superposition state is an outstanding goal of cavity optomechanics. Here, we propose a technique to generate cat states of motion using the intrinsic nonlinearity of …
View article: Homodyne measurement with a Schrödinger cat state as a local oscillator
Homodyne measurement with a Schrödinger cat state as a local oscillator Open
Homodyne measurements are a widely used quantum measurement. Using a coherent state of large amplitude as the local oscillator, it can be shown that the quantum homodyne measurement limits to a field quadrature measurement. In this work, w…
View article: Building a Quantum Engineering Undergraduate Program
Building a Quantum Engineering Undergraduate Program Open
Contribution: A roadmap is provided for building a quantum engineering education program to satisfy U.S. national and international workforce needs. Background: The rapidly growing quantum information science and engineering (QISE)…
View article: Projection-operator-based Newton method for the trajectory optimization of closed quantum systems
Projection-operator-based Newton method for the trajectory optimization of closed quantum systems Open
Quantum optimal control is an important technology that enables fast state preparation and gate design. In the absence of an analytic solution, most quantum optimal control methods rely on an iterative scheme to update the solution estimat…
View article: Master equations and quantum trajectories for squeezed wave packets
Master equations and quantum trajectories for squeezed wave packets Open
The interaction between matter and squeezed light has mostly been treated within the approximation that the field-correlation time is small. Methods for treating squeezed light with more general correlations currently involve explicitly mo…
View article: Building a Quantum Engineering Undergraduate Program
Building a Quantum Engineering Undergraduate Program Open
The rapidly growing quantum information science and engineering (QISE) industry will require both quantum-aware and quantum-proficient engineers at the bachelor's level. We provide a roadmap for building a quantum engineering education pro…
View article: Quantum limits on noise for a class of nonlinear amplifiers
Quantum limits on noise for a class of nonlinear amplifiers Open
Nonlinear amplifiers such as the transistor are ubiquitous in classical technology, but their quantum analogues are not well understood. We introduce a class of nonlinear amplifiers that amplify any normal operator and add only a half-quan…
View article: Precisely determining photon-number in real-time
Precisely determining photon-number in real-time Open
Superconducting transition-edge sensors (TES) are extremely sensitive microcalorimeters used as photon detectors with unparalleled energy resolution. They have found application from measuring astronomical spectra through to determining th…
View article: Quantum noise limits for a class of nonlinear amplifiers
Quantum noise limits for a class of nonlinear amplifiers Open
Nonlinear amplifiers, such as the transistor, are ubiquitous in classical technology. Little is understood about the noise properties and applications of quantum nonlinear amplifiers. We introduce a class of nonlinear amplifiers that allow…
View article: Proposal to the American Institute of Mathematics for Workshop on Coherent Quantum Feedback Control.
Proposal to the American Institute of Mathematics for Workshop on Coherent Quantum Feedback Control. Open
View article: Quantum Hypercube States
Quantum Hypercube States Open
We introduce quantum hypercube states, a class of continuous-variable quantum states that are generated as orthographic projections of hypercubes onto the quadrature phase space of a bosonic mode. In addition to their interesting geometry,…
View article: Bayesian ACRONYM Tuning
Bayesian ACRONYM Tuning Open
We provide an algorithm that uses Bayesian randomized benchmarking in concert with a local optimizer, such as SPSA, to find a set of controls that optimizes that average gate fidelity. We call this method Bayesian ACRONYM tuning as a refer…
View article: Two-photon self-Kerr nonlinearities for quantum computing and quantum optics
Two-photon self-Kerr nonlinearities for quantum computing and quantum optics Open
The self-Kerr interaction is an optical nonlinearity that produces a phase\nshift proportional to the square of the number of photons in the field. At\npresent, many proposals use nonlinearities to generate photon-photon\ninteractions. For…
View article: Hypercube States for Sub-Planck Sensing
Hypercube States for Sub-Planck Sensing Open
View article: Nonreciprocity Realized with Quantum Nonlinearity
Nonreciprocity Realized with Quantum Nonlinearity Open
Nonreciprocal devices are a key element for signal routing and noise isolation. Rapid development of quantum technologies has boosted the demand for a new generation of miniaturized and low-loss nonreciprocal components. Here, we use a pai…
View article: Nonreciprocal atomic scattering: A saturable, quantum Yagi-Uda antenna
Nonreciprocal atomic scattering: A saturable, quantum Yagi-Uda antenna Open
Recent theoretical studies of a pair of atoms in a 1D waveguide find that the system responds asymmetrically to incident fields from opposing directions at low powers. Since there is no explicit time-reversal symmetry breaking elements in …
View article: Qubit models of weak continuous measurements
Qubit models of weak continuous measurements Open
In this paper we approach the theory of continuous measurements and the associated unconditional and conditional (stochastic) master equations from the perspective of quantum information and quantum computing. We do so by showing how the c…
View article: Quantum trajectories for propagating Fock states
Quantum trajectories for propagating Fock states Open
We derive quantum trajectories (also known as stochastic master equations)\nthat describe an arbitrary quantum system probed by a propagating wave packet\nof light prepared in a continuous-mode Fock state. We consider three detection\nsche…