Results for "Jay M. Gambetta"

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Purcell effect with microwave drive: Suppression of qubit relaxation rateJan 22 2014Mar 21 2014We analyze the Purcell relaxation rate of a superconducting qubit coupled to a resonator, which is coupled to a transmission line and pumped by an external microwave drive. Considering the typical regime of the qubit measurement, we focus on the case ... More
Maximum Likelihood, Minimum EffortJun 27 2011Sep 07 2011We provide an efficient method for computing the maximum likelihood mixed quantum state (with density matrix rho) given a set of measurement outcome in a complete orthonormal operator basis subject to Gaussian noise. Our method works by first changing ... More
Characterization of hidden modes in networks of superconducting qubitsMar 13 2017Dec 05 2017We present a method for detecting electromagnetic (EM) modes that couple to a superconducting qubit in a circuit-QED architecture. Based on measurement-induced dephasing, this technique allows the measurement of modes that have a high quality factor (Q) ... More
Coherent Control of a Superconducting Qubit with Dynamically Tunable Qubit-cavity CouplingAug 12 2011We demonstrate coherent control and measurement of a superconducting qubit coupled to a superconducting coplanar waveguide resonator with a dynamically tunable qubit-cavity coupling strength. Rabi oscillations are measured for several coupling strengths ... More
Characterizing a Four-Qubit Planar Lattice for Arbitrary Error DetectionSep 09 2015Quantum error correction will be a necessary component towards realizing scalable quantum computers with physical qubits. Theoretically, it is possible to perform arbitrarily long computations if the error rate is below a threshold value. The two-dimensional ... More
Time-Reversal Symmetrization of Spontaneous Emission for High Fidelity Quantum State TransferAug 15 2013We demonstrate the ability to control the spontaneous emission from a superconducting qubit coupled to a cavity. The time domain profile of the emitted photon is shaped into a symmetric truncated exponential. The experiment is enabled by a qubit coupled ... More
Charge insensitive qubit design derived from the Cooper pair boxFeb 28 2007Sep 26 2007Short dephasing times pose one of the main challenges in realizing a quantum computer. Different approaches have been devised to cure this problem for superconducting qubits, a prime example being the operation of such devices at optimal working points, ... More
Tomography via Correlation of Noisy Measurement RecordsOct 24 2013Dec 20 2013We present methods and results of shot-by-shot correlation of noisy measurements to extract entangled state and process tomography in a superconducting qubit architecture. We show that averaging continuous values, rather than counting discrete thresholded ... More
Verifying Multipartite Entangled GHZ States via Multiple Quantum CoherencesMay 14 2019The ability to generate and verify multipartite entanglement is an important benchmark for near-term quantum devices devices. We develop a scalable entanglement metric based on multiple quantum coherences, and demonstrate experimentally on a 20-qubit ... More
Efficient measurement of quantum gate error by interleaved randomized benchmarkingMar 20 2012Mar 19 2014We describe a scalable experimental protocol for obtaining estimates of the error rate of individual quantum computational gates. This protocol, in which random Clifford gates are interleaved between a gate of interest, provides a bounded estimate of ... More
Quantum optimization using variational algorithms on near-term quantum devicesOct 03 2017Oct 09 2017Universal fault-tolerant quantum computers will require error-free execution of long sequences of quantum gate operations, which is expected to involve millions of physical qubits. Before the full power of such machines will be available, near-term quantum ... More
Quantum non-demolition measurement of microwave photons using engineered quadratic interactionsAug 19 2010We present a quantum electrical circuit with Josephson junctions formed of two anharmonic oscillators coupled with an interaction $g\gamma_{1}^{2}\gamma_{2}^{2}$ where $\gamma_{1}$ and $\gamma_{2}$ are position-like coordinates. This type of coupling ... More
Stochastic simulations of conditional states of partially observed systems, quantum and classicalMar 31 2005Apr 06 2007In a partially observed quantum or classical system the information that we cannot access results in our description of the system becoming mixed even if we have perfect initial knowledge. That is, if the system is quantum the conditional state will be ... More
A perturbative approach to non-Markovian stochastic Schrödinger equationsAug 28 2002Apr 14 2007In this paper we present a perturbative procedure that allows one to numerically solve diffusive non-Markovian Stochastic Schr\"odinger equations, for a wide range of memory functions. To illustrate this procedure numerical results are presented for a ... More
The non-Markovian stochastic Schrödinger equation for the position unravelingMay 09 2003Apr 14 2007An important and well established area of quantum optics is the theory of Markovian stochastic Schr\"odinger equations (or by another name quantum trajectory theory). Recently stochastic Schr\"odinger equations have been developed for non-Markovian systems. ... More
Non-Markovian stochastic Schrödinger equations: Generalization to real-valued noise using quantum measurement theoryFeb 20 2002Apr 14 2007Do stochastic Schr\"odinger equations, also known as unravelings, have a physical interpretation? In the Markovian limit, where the system {\em on average} obeys a master equation, the answer is yes. Markovian stochastic Schr\"odinger equations generate ... More
The interpretation of non-Markovian stochastic Schrödinger equations as a hidden-variable theoryJul 10 2003Apr 14 2007Do diffusive non-Markovian stochastic Schr\"odinger equations (SSEs) for open quantum systems have a physical interpretation? In a recent paper [Phys. Rev. A 66, 012108 (2002)] we investigated this question using the orthodox interpretation of quantum ... More
State and dynamical parameter estimation for open quantum systemsMar 08 2001Apr 14 2007Following the evolution of an open quantum system requires full knowledge of its dynamics. In this paper we consider open quantum systems for which the Hamiltonian is ``uncertain''. In particular, we treat in detail a simple system similar to that considered ... More
Modal dynamics for positive operator measuresJun 21 2003Apr 06 2007The modal interpretation of quantum mechanics allows one to keep the standard classical definition of realism intact. That is, variables have a definite status for all time and a measurement only tells us which value it had. However, at present modal ... More
Pre-Hausdorff SpacesMar 07 2008This paper introduces three separation conditions for topological spaces, called T_{0,1}, T_{0,2} ("pre-Hausdorff"), and T_{1,2}. These conditions generalize the classical T_(1) and T_(2) separation axioms, and they have advantages over them topologically ... More
Are dynamical quantum jumps detector-dependent?Oct 01 2011Apr 19 2012Dynamical quantum jumps were initially conceived by Bohr as objective events associated with the emission of a light quantum by an atom. Since the early 1990s they have come to be understood as being associated rather with the detection of a photon by ... More
Characterizing Quantum Gates via Randomized BenchmarkingSep 30 2011Apr 27 2012We describe and expand upon the scalable randomized benchmarking protocol proposed in Phys. Rev. Lett. 106, 180504 (2011) which provides a method for benchmarking quantum gates and estimating the gate-dependence of the noise. The protocol allows the noise ... More
Jump-like unravelings for non-Markovian open quantum systemsJan 27 2004Apr 06 2007Non-Markovian evolution of an open quantum system can be `unraveled' into pure state trajectories generated by a non-Markovian stochastic (diffusive) Schr\"odinger equation, as introduced by Di\'osi, Gisin, and Strunz. Recently we have shown that such ... More
Dynamical parameter estimation using realistic photodetectionJan 13 2004Apr 14 2007We investigate the effect of imperfections in realistic detectors upon the problem of quantum state and parameter estimation by continuous monitoring of an open quantum system. Specifically, we have reexamined the system of a two-level atom with an unknown ... More
Error mitigation for short depth quantum circuitsDec 06 2016Two schemes are presented that mitigate the effect of errors and decoherence in short depth quantum circuits. The size of the circuits for which these techniques can be applied is limited by the rate at which the errors in the computation are introduced. ... More
Optimized pulse shapes for a resonator-induced phase gateNov 20 2014Apr 06 2015The resonator-induced phase gate is a multi-qubit controlled-phase gate for fixed-frequency superconducting qubits. Through off-resonant driving of a bus resonator, statically coupled qubits acquire a state-dependent phase. However, photon loss leads ... More
On Mixing Supersymmetry and Family Symmetry BreakingsSep 26 2012Mar 11 2013We present a toy model in which the Higgs sector fields transform as non-Abelian representations of a family symmetry group, and consider the possibility that the extra family partners of the Higgs particles act as messengers for both supersymmetry and ... More
Detector dependency of diffusive quantum monitoringsMay 01 2015Continuous measurements play a pivotal role in the study of dynamical open quantum systems. `Dyne' detections are among the most widespread and efficient measurement schemes, and give rise to quantum diffusion of the conditioned state. In this work we ... More
Procedure for systematically tuning up crosstalk in the cross resonance gateMar 15 2016We present improvements in both theoretical understanding and experimental implementation of the cross resonance (CR) gate that have led to shorter two-qubit gate times and interleaved randomized benchmarking fidelities exceeding 99%. The CR gate is an ... More
Building logical qubits in a superconducting quantum computing systemOct 15 2015The technological world is in the midst of a quantum computing and quantum information revolution. Since Richard Feynman's famous "plenty of room at the bottom" lecture, hinting at the notion of novel devices employing quantum mechanics, the quantum information ... More
Josephson junction-embedded transmission-line resonators: from Kerr medium to in-line transmonApr 10 2012Jul 17 2012We provide a general method to find the Hamiltonian of a linear circuit in the presence of a nonlinearity. Focussing on the case of a Josephson junction embedded in a transmission-line resonator, we solve for the normal modes of the system by taking into ... More
Model for monitoring of a charge qubit using a radio-frequency quantum point contact including experimental imperfectionsJun 24 2007Mar 06 2008The extension of quantum trajectory theory to incorporate realistic imperfections in the measurement of solid-state qubits is important for quantum computation, particularly for the purposes of state preparation and error-correction as well as for readout ... More
Leakage Suppression in the Toric CodeOct 30 2014Quantum codes excel at correcting local noise but fail to correct leakage faults that excite qubits to states outside the computational space. Aliferis and Terhal have shown that an accuracy threshold exists for leakage faults using gadgets called leakage ... More
Classical Stochastic Discrete Time CrystalsMay 21 2019We describe a possible general and simple paradigm in a classical thermal setting for discrete time crystals (DTCs), systems with stable dynamics which is subharmonic to the driving frequency thus breaking discrete time-translational invariance. We consider ... More
Deflatability of Permutation ClassesSep 18 2014A deflatable permutation class is one in which the simple permutations are contained in a proper subclass. Deflatable permutation classes are often easier to describe and enumerate than non-deflatable ones. Some theorems which guarantee non-deflatability ... More
Crack-Like Processes Governing the Onset of Frictional SlipMar 20 2006We perform real-time measurements of the net contact area between two blocks of like material at the onset of frictional slip. We show that the process of interface detachment, which immediately precedes the inception of frictional sliding, is governed ... More
Far-Ultraviolet Spectroscopy of Star-Forming Regions in Nearby Galaxies: Stellar Populations and Abundance IndicatorsMar 20 2004We present FUSE spectroscopy and supporting data for star-forming regions in nearby galaxies, to examine their massive-star content and explore the use of abundance and population indicators in this spectral range for high-redshift galaxies. New far-ultraviolet ... More
Inclusion properties for bi-univalent functions of complex order defined by combining of Faber polynomial expansions and Fibonacci numbersJan 13 2019In this present investigation, we introduce the new class R of bi-univalent functions defined by using the Tremblay fractional derivative operator. Additionally, we use the Faber polynomial expansions and Fibonacci numbers to derive bounds for the general ... More
Comparing Spatial Regression to Random Forests for Large Environmental Data SetsDec 26 2018Environmental data may be "large" due to number of records, number of covariates, or both. Random forests has a reputation for good predictive performance when using many covariates with nonlinear relationships, whereas spatial regression, when using ... More
A Point Process Model for Generating Biofilms with Realistic Microstructure and RheologyJul 16 2017Biofilms are communities of bacteria that exhibit a multitude of multiscale biomechanical behaviors. Recent experimental advances have lead to characterizations of these behaviors in terms of measurements of the viscoelastic moduli of biofilms grown in ... More
Anomalies and fluctuations of near-surface air temperature at Tianhuangping (Zhejiang), China, produced by the longest total solar eclipse of the 21st century under cloudy skiesMay 09 2019We analyze the near-surface air temperature response, at three different heights over the ground, recorded by the Williams College expedition under meteorological conditions characterized by cloudy skies during the longest total solar eclipse of the 21st ... More
Rapid Driven Reset of a Qubit Readout ResonatorMar 04 2015May 22 2015Using a circuit QED device, we demonstrate a simple qubit measurement pulse shape that yields fast ring-up and ring-down of the readout resonator regardless of the qubit state. The pulse differs from a square pulse only by the inclusion of additional ... More
Microwave-activated conditional-phase gate for superconducting qubitsJul 09 2013We introduce a new entangling gate between two fixed-frequency qubits statically coupled via a microwave resonator bus which combines the following desirable qualities: all-microwave control, appreciable qubit separation for reduction of crosstalk and ... More
Quantum trajectory approach to circuit QED: Quantum jumps and the Zeno effectSep 26 2007Jan 25 2008We present a theoretical study of a superconducting charge qubit dispersively coupled to a transmission line resonator. Starting from a master equation description of this coupled system and using a polaron transformation, we obtain an exact effective ... More
Investigating the limits of randomized benchmarking protocolsAug 13 2013In this paper, we analyze the performance of randomized benchmarking protocols on gate sets under a variety of realistic error models that include systematic rotations, amplitude damping, leakage to higher levels, and 1/f noise. We find that, in almost ... More
Efficient Z-Gates for Quantum ComputingDec 02 2016For superconducting qubits, microwave pulses drive rotations around the Bloch sphere. Here we show that the phase of these drives can be used to generate zero-duration arbitrary Z-gates which, combined with two $X_{\pi/2}$ gates, can generate any SU(2) ... More
Extending the computational reach of a noisy superconducting quantum processorMay 11 2018Quantum computation, a completely different paradigm of computing, benefits from theoretically proven speed-ups for certain problems and opens up the possibility of exactly studying the properties of quantum systems. Yet, because of the inherent fragile ... More
A universal gate for fixed-frequency qubits via a tunable busApr 11 2016Aug 18 2016A challenge for constructing large circuits of superconducting qubits is to balance addressability, coherence and coupling strength. High coherence can be attained by building circuits from fixed-frequency qubits, however, leading techniques cannot couple ... More
Characterizing errors on qubit operations via iterative randomized benchmarkingApr 24 2015With improved gate calibrations reducing unitary errors, we achieve a benchmarked single-qubit gate fidelity of 99.95% with superconducting qubits in a circuit quantum electrodynamics system. We present a method for distinguishing between unitary and ... More
Reducing Spontaneous Emission in Circuit Quantum Electrodynamics by a Combined Readout/Filter TechniqueApr 16 2015Oct 20 2015Physical implementations of qubits can be extremely sensitive to environmental coupling, which can result in decoherence. While efforts are made for protection, coupling to the environment is necessary to measure and manipulate the state of the qubit. ... More
Machine learning for discriminating quantum measurement trajectories and improving readoutNov 18 2014Nov 24 2014High-fidelity measurements are important for the physical implementation of quantum information protocols. Current methods for classifying measurement trajectories in superconducting qubit systems produce fidelities that are systematically lower than ... More
Scalable randomized benchmarking of non-Clifford gatesOct 09 2015Randomized benchmarking is a widely used experimental technique to characterize the average error of quantum operations. Benchmarking procedures that scale to enable characterization of $n$-qubit circuits rely on efficient procedures for manipulating ... More
High Fidelity Quantum Gates in the Presence of DispersionNov 07 2011We numerically demonstrate the control of motional degrees of freedom of an ensemble of neutral atoms in an optical lattice with a shallow trapping potential. Taking into account the range of quasimomenta across different Brillouin zones results in an ... More
Validating quantum computers using randomized model circuitsNov 30 2018We introduce a single-number metric, quantum volume, that can be measured using a concrete protocol on near-term quantum computers of modest size ($n\lesssim 50$), and measure it on several state-of-the-art transmon devices, finding values as high as ... More
Analytical determination of participation in superconducting coplanar architecturesDec 14 2017Jun 18 2018Superconducting qubits are sensitive to a variety of loss mechanisms which include dielectric loss from interfaces. The calculation of participation near the key interfaces of planar designs can be accomplished through an analytical description of the ... More
The Asymptotic Number of Simple Singular Vector Tuples of a Cubical TensorMay 19 2016Jul 12 2016S. Ekhad and D. Zeilberger recently proved that the multivariate generating function for the number of simple singular vector tuples of a generic $m_1 \times \cdots \times m_d$ tensor has an elegant rational form involving elementary symmetric functions, ... More
Generalised Gelfand-Graev Representations in Small CharacteristicsAug 07 2014Sep 14 2015Let $\mathbf{G}$ be a connected reductive algebraic group over an algebraic closure $\overline{\mathbb{F}_p}$ of the finite field of prime order $p$ and let $F : \mathbf{G} \to \mathbf{G}$ be a Frobenius endomorphism with $G = \mathbf{G}^F$ the corresponding ... More
Evaluating Characteristic Functions of Character Sheaves at Unipotent ElementsMar 29 2014Sep 16 2014Assume $\mathbf{G}$ is a connected reductive algebraic group defined over an algebraic closure $\mathbb{K} = \overline{\mathbb{F}}_p$ of the finite field of prime order $p>0$. Furthermore, assume that $F : \mathbf{G} \to \mathbf{G}$ is a Frobenius endomorphism ... More
Induced Characters of Type D Weyl Groups and the Littlewood-Richardson RuleAug 18 2014Nov 04 2014For any ordinary irreducible character of a maximal reflection subgroup of type $D_aD_b$ of a type $D$ Weyl group we give an explicit decomposition of the induced character in terms of Littlewood-Richardson coefficients.
Optimal Multistage Sampling in a Boundary-Crossing ProblemMay 11 2011Brownian motion with known positive drift is sampled in stages until it crosses a positive boundary $a$. A family of multistage samplers that control the expected overshoot over the boundary by varying the stage size at each stage is shown to be optimal ... More
A New Characterization of Elfving's Method for High Dimensional ComputationOct 30 2011We give a new characterization of Elfving's (1952) method for computing c-optimal designs in k dimensions which gives explicit formulae for the k unknown optimal weights and k unknown signs in Elfving's characterization. This eliminates the need to search ... More
Several Convex-Ear DecompositionsMay 09 2006In this paper we give convex-ear decompositions for the order complexes of several classes of posets, namely supersolvable lattices with non-zero Mobius functions and rank-selected subposets of such lattices, rank-selected geometric lattices, and rank-selected ... More
A Proof of the Bomber Problem's Spend-It-All ConjectureMar 01 2011The Bomber Problem concerns optimal sequential allocation of partially effective ammunition $x$ while under attack from enemies arriving according to a Poisson process over a time interval of length $t$. In the doubly-continuous setting, in certain regions ... More
Bistable switching asymptotics for the self regulating geneJul 16 2014Mar 06 2015A simple stochastic model of a self regulating gene that displays bistable switching is analyzed. While on, a gene transcribes mRNA at a constant rate. Transcription factors can bind to the DNA and affect the gene's transcription rate. Before an mRNA ... More
Asymptotically optimal multistage tests of simple hypothesesDec 05 2007A family of variable stage size multistage tests of simple hypotheses is described, based on efficient multistage sampling procedures. Using a loss function that is a linear combination of sampling costs and error probabilities, these tests are shown ... More
Action of Automorphisms on Irreducible Characters of Symplectic GroupsDec 09 2016Assume $G$ is a finite symplectic group $\mathrm{Sp}_{2n}(q)$ over a finite field $\mathbb{F}_q$ of odd characteristic. We describe the action of the automorphism group $\mathrm{Aut}(G)$ on the set $\mathrm{Irr}(G)$ of ordinary irreducible characters ... More
Protocols for optimal readout of qubits using a continuous quantum nondemolition measurementJan 04 2007Dec 24 2007We study how the spontaneous relaxation of a qubit affects a continuous quantum non-demolition measurement of the initial state of the qubit. Given some noisy measurement record $\Psi$, we seek an estimate of whether the qubit was initially in the ground ... More
Entanglement Metrology Using a Joint Readout of Superconducting QubitsAug 13 2009Accurate and precise detection of multi-qubit entanglement is key for the experimental development of quantum computation. Traditionally, non-classical correlations between entangled qubits are measured by counting coincidences between single-shot readouts ... More
Randomized benchmarking and process tomography for gate errors in a solid-state qubitNov 26 2008We present measurements of single-qubit gate errors for a superconducting qubit. Results from quantum process tomography and randomized benchmarking are compared with gate errors obtained from a double pi pulse experiment. Randomized benchmarking reveals ... More
Effective Theories of Flavor and the Non-Universal MSSMJul 22 2016Flavor symmetries \`a la Froggatt-Nielsen~(FN) provide a compelling way to explain the hierarchies of fermionic masses and mixing angles in the Yukawa sector. In Supersymmetric (SUSY) extensions of the Standard Model where the mediation of SUSY breaking ... More
Effective Theories of Flavor and the Non-Universal MSSMJul 22 2016Feb 07 2017Flavor symmetries \`{a} la Froggatt-Nielsen~(FN) provide a compelling way to explain the hierarchies of fermionic masses and mixing angles in the Yukawa sector. In Supersymmetric~(SUSY) extensions of the Standard Model where the mediation of SUSY breaking ... More
Limited processivity of single motors improves overall transport flux of self-assembled motor-cargo complexesFeb 26 2019Single kinesin molecular motors can processively move along a microtubule (MT) a few micrometers on average before dissociating. However, cellular length scales over which transport occurs are several hundred microns and more. Why seemingly unreliable ... More
Investigating surface loss effects in superconducting transmon qubitsMay 25 2016Superconducting qubits are sensitive to a variety of loss mechanisms including dielectric loss from interfaces. By changing the physical footprint of the qubit it is possible to modulate sensitivity to surface loss. Here we show a systematic study of ... More
Non-monotonic diffusion rates in atom-optics Lévy kicked rotorApr 29 2019May 06 2019The dynamics of chaotic Hamiltonian systems such as the kicked rotor continues to guide our understanding of transport and localization processes. The localized states of the quantum kicked rotor decay due to decoherence effects if subjected to stationary ... More
Theory of domain formation in inhomogeneous ferromagnetic dipolar condensatesApr 07 2009Recent experimental studies of $^{87}$Rb spinor Bose Einstein condensates have shown the existence of a magnetic field driven quantum phase transition accompanied by structure formation on the ferromagnetic side of the transition. In this theoretical ... More
Dynamical evidence for a strong tidal interaction between the Milky Way and its satellite, Leo VAug 19 2016Jan 09 2017We present a chemodynamical analysis of the Leo~V dwarf galaxy, based on Keck II DEIMOS spectra of 8 member stars. We find a systemic velocity for the system of $\langle v_r\rangle = 170.9^{+ 2.1}_{-1.9}$kms$^{-1}$, and barely resolve a velocity dispersion ... More
The White Dwarfs within 20 Parsecs of the Sun: Kinematics and StatisticsOct 07 2009Oct 08 2009We present the kinematical properties, distribution of spectroscopic subtypes, stellar population subcomponents of the white dwarfs within 20 pc of the sun. We find no convincing evidence of halo white dwarfs in the total 20 pc sample of 129 white dwarfs ... More
Robustness of Majorana fermions in 2D topological superconductorsDec 22 2009Sep 30 2010In 2D chiral p-wave superconductors, the zero-energy Majorana fermion excitations trapped at vortex cores follow non-Abelian statistics which can be potentially exploited to build a topological quantum computer. The Majorana states are protected from ... More
A generic new platform for topological quantum computation using semiconductor heterostructuresJul 13 2009Jan 12 2010We show that a film of a semiconductor such as GaAs, in which s-wave superconductivity and a Zeeman splitting are induced by proximity effect, supports zero-energy Majorana fermion modes in the ordinary vortex excitations. The key to the topological order ... More
Topological Yu-Shiba-Rusinov chain from spin-orbit couplingJul 23 2014Feb 20 2015We investigate the possibility of realizing a topological state in the impurity band formed by a chain of classical spins embedded in a two-dimensional singlet superconductor with Rashba spin-orbit coupling. In contrast to similar proposals which require ... More
Detecting arbitrary quantum errors via stabilizer measurements on a sublattice of the surface codeOct 23 2014To build a fault-tolerant quantum computer, it is necessary to implement a quantum error correcting code. Such codes rely on the ability to extract information about the quantum error syndrome while not destroying the quantum information encoded in the ... More
Intrinsic Absorption Properties in Active Galaxies Observed with the Far Ultraviolet Spectroscopic ExplorerJul 01 2008In a continuing survey of active galactic nuclei observed by the Far Ultraviolet Spectroscopic Explorer, we provide a deeper analysis of intrinsic absorption features found in 35 objects. Our survey is for low-redshift and moderate-luminosity objects, ... More
Aeolus: A Markov--Chain Monte Carlo code for mapping ultracool atmospheres. An application on Jupiter and brown dwarf HST light curvesOct 14 2015Deducing the cloud cover and its temporal evolution from the observed planetary spectra and phase curves can give us major insight into the atmospheric dynamics. In this paper, we present Aeolus, a Markov-Chain Monte Carlo code that maps the structure ... More
Broadband Filters for Abatement of Spontaneous Emission in Circuit Quantum ElectrodynamicsAug 07 2015Oct 29 2015The ability to perform fast, high-fidelity readout of quantum bits (qubits) is essential to the goal of building a quantum computer. However, coupling a fast measurement channel to a superconducting qubit typically also speeds up its relaxation via spontaneous ... More
Demonstration of weight-four parity measurements in the surface code architectureMay 04 2016May 05 2016We present parity measurements on a five-qubit lattice with connectivity amenable to the surface code quantum error correction architecture. Using all-microwave controls of superconducting qubits coupled via resonators, we encode the parities of four ... More
Supervised learning with quantum enhanced feature spacesApr 30 2018Jun 05 2018Machine learning and quantum computing are two technologies each with the potential for altering how computation is performed to address previously untenable problems. Kernel methods for machine learning are ubiquitous for pattern recognition, with support ... More
Quantum information processing with circuit quantum electrodynamicsDec 01 2006Jun 01 2007We theoretically study single and two-qubit dynamics in the circuit QED architecture. We focus on the current experimental design [Wallraff et al., Nature 431, 162 (2004); Schuster et al., Nature 445, 515 (2007)] in which superconducting charge qubits ... More
Bulk and surface loss in superconducting transmon qubitsSep 13 2015Decoherence of superconducting transmon qubits is purported to be consistent with surface loss from two-level systems on the substrate surface. Here, we present a study of surface loss in transmon devices, explicitly designed to have varying sensitivities ... More
High Resolution Rapid Response observations of compact radio sources with the Ceduna Hobart Interferometer (CHI)Jan 25 2012Context. Frequent, simultaneous observations across the electromagnetic spectrum are essential to the study of a range of astrophysical phenomena including Active Galactic Nuclei. A key tool of such studies is the ability to observe an object when it ... More
Evidence that self-similar microrheology of highly entangled polymeric solutions scales robustly with, and is tunable by, polymer concentrationOct 15 2018We report observations of a remarkable scaling behavior with respect to concentration in the passive microbead rheology of two highly entangled polymeric solutions, polyethylene oxide (PEO) and hyaluronic acid (HA). This behavior was reported previously ... More
Suppressing Charge Noise Decoherence in Superconducting Charge QubitsDec 20 2007We present an experimental realization of the transmon qubit, an improved superconducting charge qubit derived from the Cooper pair box. We experimentally verify the predicted exponential suppression of sensitivity to 1/f charge noise [J. Koch et al., ... More
Controlling the spontaneous emission of a superconducting transmon qubitMar 31 2008We present a detailed characterization of coherence in seven transmon qubits in a circuit QED architecture. We find that spontaneous emission rates are strongly influenced by far off-resonant modes of the cavity and can be understood within a semiclassical ... More
Random Flag Complexes and Asymptotic SyzygiesJun 05 2017We use the probabilistic method to construct examples of conjectured phenomenon about asymptotic syzygies. In particular, we use the Stanley-Reisner ideals of random flag complexes to construct new examples of Ein and Lazarsfeld's nonvanishing for asymptotic ... More
Volumetric variational principles for a class of partial differential equations defined on surfaces and curvesJun 09 2017Dec 25 2017In this paper, we propose simple numerical algorithms for partial differential equations (PDEs) defined on closed, smooth surfaces (or curves). In particular, we consider PDEs that originate from variational principles defined on the surfaces; these include ... More
Person as Population: A Longitudinal View of Single-Subject Causal Inference for Analyzing Self-Tracked Health DataJan 10 2019Jan 22 2019Single-subject health data are becoming increasingly available thanks to advances in self-tracking technology (e.g., wearable devices, mobile apps, sensors, implants). Many users and health caregivers seek to use such observational time series data to ... More
Variable Viscosity and Density Biofilm Simulations using an Immersed Boundary Method, Part II: Experimental Validation and the Heterogeneous Rheology-IBMApr 28 2015Apr 30 2015The goal of this work is to develop a numerical simulation that accurately captures the biomechanical response of bacterial biofilms and their associated extracellular matrix (ECM). In this, the second of a two-part effort, the primary focus is on formally ... More
Projective Dimension, Graph Domination Parameters, and Independence Complex HomologyOct 13 2011Oct 22 2011We construct several pairwise-incomparable bounds on the projective dimensions of edge ideals. Our bounds use combinatorial properties of the associated graphs; in particular we draw heavily from the topic of dominating sets. Through Hochster's Formula, ... More
On the Rearrangement Conjecture for Generalized Factor Order Over $\mathbb{P}$Mar 20 2014Sep 11 2014The Rearrangement Conjecture states that if two words over $\mathbb{P}$ are Wilf-equivalent in the factor order on $\mathbb{P}^\ast$ then they are rearrangements of each other. We introduce the notion of strong Wilf-equivalence and prove that if two words ... More
Constraints on the effective fluid theory of stationary branesJun 30 2014Oct 09 2014We develop further the effective fluid theory of stationary branes. This formalism applies to stationary blackfolds as well as to other equilibrium brane systems at finite temperature. The effective theory is described by a Lagrangian containing the information ... More
Black Holes and Biophysical (Mem)-branesFeb 25 2014Nov 26 2014We argue that the effective theory describing the long-wavelength dynamics of black branes is the same effective theory that describes the dynamics of biophysical membranes. We improve the phase structure of higher-dimensional black rings by considering ... More