41 results on '"Biercuk, Michael J."'
Search Results
2. Adaptive characterization of spatially inhomogeneous fields and errors in qubit registers
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Gupta, Riddhi Swaroop, Edmunds, Claire L., Milne, Alistair R., Hempel, Cornelius, and Biercuk, Michael J.
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- 2020
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3. Predicting molecular vibronic spectra using time-domain analog quantum simulation.
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MacDonell, Ryan J., Navickas, Tomas, Wohlers-Reichel, Tim F., Valahu, Christophe H., Rao, Arjun D., Millican, Maverick J., Currington, Michael A., Biercuk, Michael J., Tan, Ting Rei, Hempel, Cornelius, and Kassal, Ivan
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- 2023
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4. Optimised Bayesian system identification in quantum devices
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Stace, Thomas M., Chen, Jiayin, Li, Li, Perunicic, Viktor S., Carvalho, Andre R. R., Hush, Michael R., Valahu, Christophe H., Tan, Ting Rei, and Biercuk, Michael J.
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Quantum Physics ,FOS: Physical sciences ,Quantum Physics (quant-ph) - Abstract
Identifying and calibrating quantitative dynamical models for physical quantum systems is important for a variety of applications. Here we present a closed-loop Bayesian learning algorithm for estimating multiple unknown parameters in a dynamical model, using optimised experimental "probe" controls and measurement. The estimation algorithm is based on a Bayesian particle filter, and is designed to autonomously choose informationally-optimised probe experiments with which to compare to model predictions. We demonstrate the performance of the algorithm in both simulated calibration tasks and in an experimental single-qubit ion-trap system. Experimentally, we find that with 60x fewer samples, we exceed the precision of conventional calibration methods, delivering an approximately 93x improvement in efficiency (as quantified by the reduction of measurements required to achieve a target residual uncertainty and multiplied by the increase in accuracy). In simulated and experimental demonstrations, we see that successively longer pulses are selected as the posterior uncertainty iteratively decreases, leading to an exponential improvement in the accuracy of model parameters with the number of experimental queries., 18 pages, 8 figures
- Published
- 2022
5. Direct observation of geometric phase in dynamics around a conical intersection
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Valahu, Christophe H., Olaya-Agudelo, Vanessa C., MacDonell, Ryan J., Navickas, Tomas, Rao, Arjun D., Millican, Maverick J., Pérez-Sánchez, Juan B., Yuen-Zhou, Joel, Biercuk, Michael J., Hempel, Cornelius, Tan, Ting Rei, and Kassal, Ivan
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Quantum Physics ,FOS: Physical sciences ,Quantum Physics (quant-ph) - Abstract
Conical intersections are ubiquitous in chemistry, often governing processes such as light harvesting, vision, photocatalysis, and chemical reactivity. They act as funnels between electronic states of molecules, allowing rapid and efficient relaxation during chemical dynamics. In addition, when a reaction path encircles a conical intersection, the molecular wavefunction experiences a geometric phase, which affects the outcome of the reaction through quantum-mechanical interference. Past experiments have measured indirect signatures of geometric phases in scattering patterns and spectroscopic observables, but there has been no direct observation of the underlying wavepacket interference. Here, we experimentally observe geometric-phase interference in the dynamics of a nuclear wavepacket travelling around an engineered conical intersection in a programmable trapped-ion quantum simulator. To achieve this, we develop a new technique to reconstruct the two-dimensional wavepacket densities of a trapped ion. Experiments agree with the theoretical model, demonstrating the ability of analog quantum simulators -- such as those realised using trapped ions -- to accurately describe nuclear quantum effects. These results demonstrate a path to deploying analog quantum simulators for solving some of the most difficult problems in chemical dynamics., 9 pages, 5 figures
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- 2022
6. Predicting molecular vibronic spectra using time-domain analog quantum simulation
- Author
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MacDonell, Ryan J., Navickas, Tomas, Wohlers-Reichel, Tim F., Valahu, Christophe H., Rao, Arjun D., Millican, Maverick J., Currington, Michael A., Biercuk, Michael J., Tan, Ting Rei, Hempel, Cornelius, and Kassal, Ivan
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Chemical Physics (physics.chem-ph) ,Quantum Physics ,Physics - Chemical Physics ,FOS: Physical sciences ,Quantum Physics (quant-ph) - Abstract
Spectroscopy is one of the most accurate probes of the molecular world. However, predicting molecular spectra accurately is computationally difficult because of the presence of entanglement between electronic and nuclear degrees of freedom. Although quantum computers promise to reduce this computational cost, existing quantum approaches rely on combining signals from individual eigenstates, an approach that is difficult to scale because the number of eigenstates grows exponentially with molecule size. Here, we introduce a method for scalable analog quantum simulation of molecular spectroscopy, by performing simulations in the time domain. Our approach can treat more complicated molecular models than previous ones, requires fewer approximations, and can be extended to open quantum systems with minimal overhead. We present a direct mapping of the underlying problem of time-domain simulation of molecular spectra to the degrees of freedom and control fields available in a trapped-ion quantum simulator. We experimentally demonstrate our algorithm on a trapped-ion device, exploiting both intrinsic electronic and motional degrees of freedom, showing excellent quantitative agreement for a single-mode vibronic photoelectron spectrum of SO$_2$., 11 pages, 8 figures
- Published
- 2022
7. Quantum computing for transport optimization
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Bentley, Christopher D. B., Marsh, Samuel, Carvalho, André R. R., Kilby, Philip, and Biercuk, Michael J.
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Quantum Physics ,FOS: Physical sciences ,Quantum Physics (quant-ph) - Abstract
We explore the near-term intersection of quantum computing with the transport sector. To support near-term integration, we introduce a framework for assessing the suitability of transport optimization problems for obtaining potential performance enhancement using quantum algorithms. Given a suitable problem, we then present a workflow for obtaining valuable transport solutions using quantum computers, articulate the limitations on contemporary systems, and describe newly available performance-enhancing tools applicable to current commercial quantum computing systems. We make this integration process concrete by following the assessment framework and integration workflow for an exemplary vehicle routing optimization problem: the Capacitated Vehicle Routing Problem. We present novel advances to exponentially reduce the required computational resources, and experimentally demonstrate a prototype implementation exhibiting over 20X circuit performance enhancement on a real quantum device., Accepted as a scientific paper for the 28th ITS World Congress 2022 Los Angeles
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- 2022
8. Walsh-synthesized noise filters for quantum logic
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Ball, Harrison and Biercuk, Michael J
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- 2015
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9. Engineered two-dimensional Ising interactions in a trapped-ion quantum simulator with hundreds of spins
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Britton, Joseph W., Sawyer, Brian C., Keith, Adam C., Wang, C.-C. Joseph, Freericks, James K., Uys, Hermann, Biercuk, Michael J., and Bollinger, John J.
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- 2012
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10. Optimized dynamical decoupling in a model quantum memory
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Biercuk, Michael J., Uys, Hermann, VanDevender, Aaron P., Shiga, Nobuyasu, Itano, Wayne M., and Bollinger, John J.
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Magnetic resonance -- Measurement -- Research -- Physiological aspects -- Psychological aspects -- Usage ,Mathematical models -- Usage -- Measurement -- Psychological aspects -- Physiological aspects -- Research ,Memory -- Physiological aspects -- Psychological aspects -- Research -- Measurement -- Usage ,Environmental issues ,Science and technology ,Zoology and wildlife conservation ,Psychological aspects ,Physiological aspects ,Usage ,Research ,Measurement - Abstract
Any quantum system, such as those used in quantum information or magnetic resonance, is subject to random phase errors that can dramatically affect the fidelity of a desired quantum operation or measurements. In the context of quantum information, quantum error correction techniques have been developed to correct these errors, but resource requirements are extraordinary. The realization of a physically tractable quantum information system will therefore be facilitated if qubit (quantum bit) error rates are far below the so-called fault-tolerance error threshold(1), predicted to be of the order Of [10.sup.-3]-[10.sup.-6]. The need to realize such low error rates motivates a search for alternative strategies to suppress dephasing in quantum systems(2). Here we experimentally demonstrate massive suppression of qubit error rates by the application of optimized dynamical decoupling(3-8) pulse sequences, using a model quantum system capable of simulating a variety of qubit technologies. We demonstrate an analytically derived pulse sequence(9), UDD, and fmd novel sequences through active, real-time experimental feedback. The latter sequences are tailored to maximize error suppression without the need for a priori knowledge of the ambient noise environment, and are capable of suppressing errors by orders of magnitude compared to other existing sequences (including the benchmark multi-pulse spin echos(10,11)). Our work includes the extension of a treatment to predict qubit decoherences(12,13)is under realistic conditions, yielding strong agreement between experimental data and theory for arbitrary pulse sequences incorporating non-idealized control pulses. These results demonstrate the robustness of qubit memory error suppression through dynamical decoupling techniques across a variety of qubit technologies(11,14-16)., We consider classical phase randomization of a qubit due to the action of the environment as the dominant source of memory errors. Accordingly, we may write a Hamiltonian as H [...]
- Published
- 2009
11. Reliable GPS is coming to an end—but new quantum technologies could show the path forward.
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Biercuk, Michael J.
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- 2024
12. Quantum Error Correction at the Threshold: If technologists don't get beyond it, quantum computers will never be big.
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Biercuk, Michael J. and Stace, Thomas M.
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QUANTUM computing , *TECHNOLOGISTS , *QUANTUM computers , *LOGIC circuits , *SEPULCHRAL monuments , *MICROELECTRONICS - Abstract
Dates Chiseled into an ancient tombstone have more in common with the data in your phone or laptop than you may realize. They both involve conventional, classical information, carried by hard-ware that is relatively immune to errors. The situation inside a quantum computer is far different: The information itself has its own idiosyncratic properties, and compared with standard digital microelectronics, state-of-the-art quantum-computer hardware is more than a billion trillion times as likely to suffer a fault. This tremendous susceptibility to errors is the single biggest problem holding back quantum computing from realizing its great promise. [ABSTRACT FROM AUTHOR]
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- 2022
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13. Software tools for quantum control: improving quantum computer performance through noise and error suppression.
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Ball, Harrison, Biercuk, Michael J, Carvalho, Andre R R, Chen, Jiayin, Hush, Michael, De Castro, Leonardo A, Li, Li, Liebermann, Per J, Slatyer, Harry J, Edmunds, Claire, Frey, Virginia, Hempel, Cornelius, and Milne, Alistair
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- 2021
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14. Autonomous adaptive noise characterization in quantum computers
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Gupta, Riddhi Swaroop, Milne, Alistair R., Edmunds, Claire L., Hempel, Cornelius, and Biercuk, Michael J.
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65M75, 62M05, 62M20, 60G35, 93E35 ,Quantum Physics ,FOS: Physical sciences ,Quantum Physics (quant-ph) - Abstract
New quantum computing architectures consider integrating qubits as sensors to provide actionable information useful for decoherence mitigation on neighboring data qubits, but little work has addressed how such schemes may be efficiently implemented in order to maximize information utilization. Techniques from classical estimation and dynamic control, suitably adapted to the strictures of quantum measurement, provide an opportunity to extract augmented hardware performance through automation of low-level characterization and control. In this work, we present an autonomous learning framework, Noise Mapping for Quantum Architectures (NMQA), for adaptive scheduling of sensor-qubit measurements and efficient spatial noise mapping (prior to actuation) across device architectures. Via a two-layer particle filter, NMQA receives binary measurements and determines regions within the architecture that share common noise processes; an adaptive controller then schedules future measurements to reduce map uncertainty. Numerical analysis and experiments on an array of trapped ytterbium ions demonstrate that NMQA outperforms brute-force mapping by up-to $18$x ($3$x) in simulations (experiments), calculated as a reduction in the number of measurements required to map a spatially inhomogeneous magnetic field with a target error metric. As an early adaptation of robotic control to quantum devices, this work opens up exciting new avenues in quantum computer science., 9 pages, 4 figures. (Supplements: 6 pages, 3 figures.)
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- 2019
15. Analog quantum simulation of chemical dynamics.
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MacDonell, Ryan J., Dickerson, Claire E., Birch, Clare J. T., Kumar, Alok, Edmunds, Claire L., Biercuk, Michael J., Hempel, Cornelius, and Kassal, Ivan
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- 2021
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16. Qiskit Backend Specifications for OpenQASM and OpenPulse Experiments
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McKay, David C., Alexander, Thomas, Bello, Luciano, Biercuk, Michael J., Bishop, Lev, Chen, Jiayin, Chow, Jerry M., C��rcoles, Antonio D., Egger, Daniel, Filipp, Stefan, Gomez, Juan, Hush, Michael, Javadi-Abhari, Ali, Moreda, Diego, Nation, Paul, Paulovicks, Brent, Winston, Erick, Wood, Christopher J., Wootton, James, and Gambetta, Jay M.
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FOS: Computer and information sciences ,Quantum Physics ,Emerging Technologies (cs.ET) ,FOS: Physical sciences ,Computer Science - Emerging Technologies ,Quantum Physics (quant-ph) - Abstract
As interest in quantum computing grows, there is a pressing need for standardized API's so that algorithm designers, circuit designers, and physicists can be provided a common reference frame for designing, executing, and optimizing experiments. There is also a need for a language specification that goes beyond gates and allows users to specify the time dynamics of a quantum experiment and recover the time dynamics of the output. In this document we provide a specification for a common interface to backends (simulators and experiments) and a standarized data structure (Qobj --- quantum object) for sending experiments to those backends via Qiskit. We also introduce OpenPulse, a language for specifying pulse level control (i.e. control of the continuous time dynamics) of a general quantum device independent of the specific hardware implementation., 68 pages. More information and schemas can be found in the Qiskit repository https://github.com/Qiskit/
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- 2018
17. Quantum firmware and the quantum computing stack.
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Ball, Harrison, Biercuk, Michael J., and Hush, Michael R.
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QUANTUM computing , *COMPUTER firmware , *ALGORITHMS - Abstract
Integrated quantum-control protocols could bridge the gap between abstract algorithms and the physical manipulation of imperfect hardware. [ABSTRACT FROM AUTHOR]
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- 2021
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18. Numeric Optimization for Configurable, Parallel, Error‐Robust Entangling Gates in Large Ion Registers.
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Bentley, Christopher D. B., Ball, Harrison, Biercuk, Michael J., Carvalho, Andre R. R., Hush, Michael R., and Slatyer, Harry J.
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A class of entangling gates for trapped atomic ions is studied and the use of numeric optimization techniques to create a wide range of fast, error‐robust gate constructions is demonstrated. A numeric optimization framework is introduced targeting maximally‐ and partially‐entangling operations on ion pairs, multi‐ion registers, multi‐ion subsets of large registers, and parallel operations within a single register. Ions are assumed to be individually addressed, permitting optimization over amplitude‐ and phase‐modulated controls. Calculations and simulations demonstrate that the inclusion of modulation of the difference phase for the bichromatic drive used in the Mølmer–Sørensen gate permits approximately time‐optimal control across a range of gate configurations, and when suitably combined with analytic constraints can also provide robustness against key experimental sources of error. The impact of experimental constraints such as bounds on coupling rates or modulation band‐limits on achievable performance is further demonstrated. Using a custom optimization engine based on TensorFlow, for optimizations on ion registers up to 20 ions, time‐to‐solution of order tens of minutes using a local‐instance laptop is also demonstrated, allowing computational access to system‐scales relevant to near‐term trapped‐ion devices. [ABSTRACT FROM AUTHOR]
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- 2020
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19. Long-time Low-latency Quantum Memory by Dynamical Decoupling
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Khodjasteh, Kaveh, Sastrawan, Jarrah, Hayes, David, Green, Todd J., Biercuk, Michael J., and Viola, Lorenza
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Quantum Physics ,FOS: Physical sciences ,Quantum Physics (quant-ph) - Abstract
Quantum memory is a central component for quantum information processing devices, and will be required to provide high-fidelity storage of arbitrary states, long storage times and small access latencies. Despite growing interest in applying physical-layer error-suppression strategies to boost fidelities, it has not previously been possible to meet such competing demands with a single approach. Here we use an experimentally validated theoretical framework to identify periodic repetition of a high-order dynamical decoupling sequence as a systematic strategy to meet these challenges. We provide analytic bounds-validated by numerical calculations-on the characteristics of the relevant control sequences and show that a "stroboscopic saturation" of coherence, or coherence plateau, can be engineered, even in the presence of experimental imperfection. This permits high-fidelity storage for times that can be exceptionally long, meaning that our device-independent results should prove instrumental in producing practically useful quantum technologies., and authors list fixed
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- 2012
20. Optimized Noise Filtration through Dynamical Decoupling
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Uys, Hermann, Biercuk, Michael J., and Bollinger, John J.
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Quantum Physics ,FOS: Physical sciences ,Quantum Physics (quant-ph) - Abstract
One approach to maintaining phase coherence of qubits through dynamical decoupling consists of applying a sequence of Hahn spin-echo pulses. Recent studies have shown that, in certain noise environments, judicious choice of the delay times between these pulses can greatly improve the suppression of phase errors compared to traditional approaches. By enforcing a simple analytical condition, we obtain sets of dynamical decoupling sequences that are designed for optimized noise filtration and are spectrum-independent up to a single scaling factor set by the coherence time of the system. We demonstrate the efficacy of these sequences in suppressing phase errors through measurements on a model qubit system, $^{9}$Be$^{+}$ ions in a Penning trap. Our combined theoretical and experimental studies show that in high-frequency-dominated noise environments this approach may suppress phase errors orders of magnitude more efficiently than comparable techniques can., 4 pages, 3 figures version 2 - Different nomenclature to describe sequences - More detailed explanation contrasting feedback routine implemented here to that in previous work - Statements on the constraints on noise spectra which will allow improved error suppression added. - Typos corrected and other minor changes made
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- 2009
21. Phase-Modulated Decoupling and Error Suppression in Qubit-Oscillator Systems.
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Green, Todd J. and Biercuk, Michael J.
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QUANTUM mechanics , *QUBITS , *ELECTRIC oscillators , *IONS , *MATHEMATICAL decoupling , *MATHEMATICAL inequalities - Abstract
We present a scheme designed to suppress the dominant source of infidelity in entangling gates between quantum systems coupled through intermediate bosonic oscillator modes. Such systems are particularly susceptible to residual qubit-oscillator entanglement at the conclusion of a gate period that reduces the fidelity of the target entangling operation. We demonstrate how the exclusive use of discrete shifts in the phase of the field moderating the qubit-oscillator interaction is sufficient to both ensure multiple oscillator modes are decoupled and to suppress the effects of fluctuations in the driving field. This approach is amenable to a wide variety of technical implementations including geometric phase gates in super-conducting qubits and the Molmer-Sorensen gate for trapped ions. We present detailed example protocols tailored to trapped-ion experiments and demonstrate that our approach has the potential to enable multiqubit gate implementation with a significant reduction in technical complexity relative to previously demonstrated protocols. [ABSTRACT FROM AUTHOR]
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- 2015
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22. Prolonging qubit coherence: dynamical decoupling schemes studied in a Penning ion trap.
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Uys, Hermann, Biercuk, Michael J., VanDevender, Aaron P., Shiga, Nobuyasu, Itano, Wayne M., and Bollinger, John J.
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- 2009
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23. Electrical Transport in Single-Wall Carbon Nanotubes.
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Biercuk, Michael J., Ilani, Shahal, Marcus, Charles M., and McEuen, Paul L.
- Abstract
We review recent progress in the measurement and understanding of the electrical properties of individual metal and semiconducting single-wall carbon nanotubes. The fundamental scattering mechanisms governing the electrical transport in nanotubes are discussed, along with the properties of p-n and Schottky-barrier junctions in semiconductor tubes. The use of advanced nanotube devices for electronic, high-frequency, and electromechanical applications is discussed. We then examine quantum transport in carbon nanotubes, including the observation of quantized conductance, proximity-induced supercurrents, and spin-dependent ballistic transport. We move on to explore the properties of single and coupled carbon-nanotube quantum dots. Spin and orbital (isospin) magnetic moments lead to fourfold shell structure and unusual Kondo phenomena. We conclude with a discussion of unanswered questions and a look to future research directions. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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24. The path to adaptive microsystems.
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Zolper, John C. and Biercuk, Michael J.
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- 2006
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25. Phenomenological study of decoherence in solid-state spin qubits due to nuclear spin diffusion.
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Biercuk, Michael J. and Bluhm, Hendrik
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DIFFUSION , *SEMICONDUCTOR nuclear counters , *MATHEMATICAL decoupling , *SPECTRAL energy distribution , *MICROSCOPY - Abstract
We present a study of the prospects for coherence preservation in solid-state spin qubits using dynamical decoupling protocols. Recent experiments have provided the first demonstrations of multipulse dynamical decoupling sequences in this qubit system, but quantitative analyses of potential coherence improvements have been hampered by a lack of concrete knowledge of the relevant noise processes. We present calculations of qubit coherence under the application of arbitrary dynamical decoupling pulse sequences based on an experimentally validated semiclassical model. This phenomenological approach bundles the details of underlying noise processes into a single experimentally relevant noise power spectral density. Our results show that the dominant features of experimental measurements in a two-electron singlet-triplet spin qubit can be replicated using a 1/ω2 noise power spectrum associated with nuclear spin flips in the host material. Beginning with this validation, we address the effects of nuclear programming, high-frequency nuclear spin dynamics, and other high-frequency classical noise sources, with conjectures supported by physical arguments and microscopic calculations where relevant. Our results provide expected performance bounds and identify diagnostic metrics that can be measured experimentally in order to better elucidate the underlying nuclear spin dynamics. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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26. Ultrasensitive detection of force and displacement using trapped ions.
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Biercuk, Michael J., Uys, Hermann, Britton, Joe W., VanDevender, Aaron P., and Bollinger, John J.
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FORCE & energy , *ION traps , *NANOSCIENCE , *IMAGING systems , *MICROSCOPY - Abstract
The ability to detect extremely small forces and nanoscale displacements is vital for disciplines such as precision spin-resonance imaging, microscopy, and tests of fundamental physical phenomena. Current force-detection sensitivity limits have surpassed 1 aN Hz−1/2 (refs 6,7) through coupling of nanomechanical resonators to a variety of physical readout systems. Here, we demonstrate that crystals of trapped atomic ions behave as nanoscale mechanical oscillators and may form the core of exquisitely sensitive force and displacement detectors. We report the detection of forces with a sensitivity of 390 ± 150 yN Hz−1/2, which is more than three orders of magnitude better than existing reports using nanofabricated devices7, and discriminate ion displacements of ∼18 nm. Our technique is based on the excitation of tunable normal motional modes in an ion trap and detection through phase-coherent Doppler velocimetry, and should ultimately allow force detection with a sensitivity better than 1 yN Hz−1/2 (ref. 16). Trapped-ion-based sensors could enable scientists to explore new regimes in materials science where augmented force, field and displacement sensitivity may be traded against reduced spatial resolution. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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27. Back Cover: Numeric Optimization for Configurable, Parallel, Error‐Robust Entangling Gates in Large Ion Registers (Adv. Quantum Technol. 11/2020).
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Bentley, Christopher D. B., Ball, Harrison, Biercuk, Michael J., Carvalho, Andre R. R., Hush, Michael R., and Slatyer, Harry J.
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- 2020
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28. Quantum computing: Solid-state spins survive.
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Biercuk, Michael J. and Reilly, David J.
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QUANTUM statistics , *QUANTUM theory , *MATHEMATICAL decoupling , *SOLID state electronics , *MATHEMATICAL inequalities , *NANOTECHNOLOGY - Abstract
The article discusses several experiments aimed to improving the fidelity of quantum control in solid-state spin quantum bits and extending their coherent lifetimes. These experiments which focused on two distinct physical implementations of qubits, have demonstrated that manipulating spins with high-speed control pulses, in a technique known as dynamical decoupling, allows for high-fidelity control and improvement in the lifetimes of integrated quantum devices.
- Published
- 2011
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29. Preserving quantum coherence using optimized open-loop control techniques.
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Biercuk, Michael J., Uys, Hermann, VanDevender, Aaron P., Shiga, Nobuyasu, Itano, Wayne M., and Bollinger, John J.
- Published
- 2010
30. Prediction and real-time compensation of qubit decoherence via machine learning.
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Mavadia, Sandeep, Frey, Virginia, Sastrawan, Jarrah, Dona, Stephen, and Biercuk, Michael J.
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- 2017
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31. Quantum measurement: A quantum spectrum analyser.
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Biercuk, Michael J.
- Subjects
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QUANTUM theory , *SUPERCONDUCTING quantum interference devices , *SPECTRAL energy distribution , *SPECTRUM analyzers , *NOISE - Abstract
The article focuses on the study of J. Bylander and colleagues which examines the quantum dynamics of a superconducting flux qubit with the use of a superconducting quantum interference device (SQUID). It says that the qubit will have decoherence problems if it freely evolves in an uncontrolled environmental noise. It mentions that the study allows noise power spectral density reconstruction and comparison against known noise mechanism.
- Published
- 2011
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32. Designing a practical high-fidelity long-time quantum memory.
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Khodjasteh, Kaveh, Sastrawan, Jarrah, Hayes, David, Green, Todd J., Biercuk, Michael J., and Viola, Lorenza
- Published
- 2013
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33. High-Order Noise Filtering in Nontrivial Quantum Logic Gates.
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Green, Todd, Uys, Hermann, and Biercuk, Michael J.
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NOISE , *QUANTUM theory , *FILTERS & filtration , *GATE array circuits , *ERROR rates , *HAMILTONIAN systems , *PERFORMANCE evaluation - Abstract
Treating the effects of a time-dependent classical dephasing environment during quantum logic operations poses a theoretical challenge, as the application of noncommuting control operations gives rise to both dephasing and depolarization errors that must be accounted for in order to understand total average error rates. We develop a treatment based on effective Hamiltonian theory that allows us to efficiently model the effect of classical noise on nontrivial single-bit quantum logic operations composed of arbitrary control sequences. We present a general method to calculate the ensemble-averaged entanglement fidelity to arbitrary order in terms of noise filter functions, and provide explicit expressions to fourth order in the noise strength. In the weak noise limit we derive explicit filter functions for a broad class of piecewise-constant control sequences, and use them to study the performance of dynamically corrected gates, yielding good agreement with brute-force numerics. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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34. Spectroscopy and Thermometry of Drumhead Modes in a Mesoscopic Trapped-Ion Crystal Using Entanglement.
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Sawyer, Brian C., Britton, Joseph W., Keith, Adam C., Wang, C.-C. Joseph, Freericks, James K., Uys, Hermann, Biercuk, Michael J., and Bollinger, John J.
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TEMPERATURE measurements , *COHERENCE (Nuclear physics) , *DIPOLE moments , *DEGREES of freedom , *ATOMIC mass , *POTENTIAL theory (Physics) - Abstract
We demonstrate spectroscopy and thermometry of individual motional modes in a mesoscopic 2D ion array using entanglement-induced decoherence as a method of transduction. Our system is a ∼400 &mgr;m-diameter planar crystal of several hundred 9Be+ ions exhibiting complex drumhead modes in the confining potential of a Penning trap. Exploiting precise control over the 9Be+ valence electron spins, we apply a homogeneous spin-dependent optical dipole force to excite arbitrary transverse modes with an effective wavelength approaching the interparticle spacing ( ∼ 20 &mgr;m). Center-of-mass displacements below 1 nm are detected via the entanglement of spin and motional degrees of freedom [ABSTRACT FROM AUTHOR]
- Published
- 2012
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35. Robustness of composite pulses to time-dependent control noise.
- Author
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Kabytayev, Chingiz, Green, Todd J., Khodjasteh, Kaveh, Biercuk, Michael J., Viola, Lorenza, and Brown, Kenneth R.
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QUBITS , *QUANTUM computing , *QUANTUM error correcting codes , *MARKOVIAN jump linear systems , *MARKOV spectrum , *NUCLEAR magnetic resonance - Abstract
We study the performance of composite pulses in the presence of time-varying control noise on a single qubit. These protocols, originally devised only to correct for static, systematic errors, are shown to be robust to time-dependent non-Markovian noise in the control field up to frequencies as high as ~10% of the Rabi frequency. Our study combines a generalized filter-function approach with asymptotic dc-limit calculations to give a simple analytic framework for error analysis applied to a number of composite-pulse sequences relevant to nuclear magnetic resonance as well as quantum information experiments. Results include examination of recently introduced concatenated composite pulses and dynamically corrected gates, demonstrating equivalent first-order suppression of time-dependent fluctuations in amplitude and/or detuning, as appropriate for the sequence in question. Our analytic results agree well with numerical simulations for realistic 1/ noise spectra with a roll-off to 1/², providing independent validation of our theoretical insights. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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36. Quantum Oscillator Noise Spectroscopy via Displaced Cat States.
- Author
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Milne, Alistair R., Hempel, Cornelius, Li Li, Edmunds, Claire L., Slatyer, Harry J., Ball, Harrison, Hush, Michael R., and Biercuk, Michael J.
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QUANTUM noise , *AMPLITUDE modulation , *PHASE modulation , *ION traps , *SPECTROMETRY , *QUBITS - Abstract
Quantum harmonic oscillators are central to many modern quantum technologies. We introduce a method to determine the frequency noise spectrum of oscillator modes through coupling them to a qubit with continuously driven qubit-state-dependent displacements. We reconstruct the noise spectrum using a series of different drive phase and amplitude modulation patterns in conjunction with a data-fusion routine based on convex optimization. We apply the technique to the identification of intrinsic noise in the motional frequency of a single trapped ion with sensitivity to fluctuations at the sub-Hz level in a spectral range from quasi-dc up to 50 kHz. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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37. Reducing sequencing complexity in dynamical quantum error suppression by Walsh modulation.
- Author
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Hayes, David, Khodjasteh, Kaveh, Viola, Lorenza, and Biercuk, Michael J.
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QUANTUM theory , *WALSH functions , *NATURAL numbers , *ERRORS , *MATHEMATICAL sequences , *LINEAR algebra , *MATHEMATICAL models - Abstract
We study dynamical error suppression from the perspective of reducing sequencing complexity, with an eye toward facilitating the development of efficient semiautonomous quantum-coherent systems. To this end, we focus on digital sequences where all interpulse time periods are integer multiples of a minimum clock period and compatibility with digital classical control circuitry is intrinsic. We use so-called Walsh functions as a unifying mathematical framework; the Walsh functions are an orthonormal set of basis functions which may be associated directly with the control propagator for a digital modulation scheme. Using this insight, we characterize the suite of resulting Walsh dynamical decoupling sequences-including both familiar and novel control sequences-and identify the number of periodic square-wave (Rademacher) functions required to generate the associated Walsh function as the key determinant of the error-suppressing features. We also show how Walsh modulation may be employed for the protection of certain nontrivial logic gates. Based on these insights, we identify Walsh modulation as a digital-efficient approach for physical-layer error suppression. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
38. Effect of noise correlations on randomized benchmarking.
- Author
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Ball, Harrison, Stace, Thomas M., Flammia, Steven T., and Biercuk, Michael J.
- Subjects
- *
QUANTUM information science , *QUANTUM noise , *QUANTUM correlations - Abstract
Among the most popular and well-studied quantum characterization, verification, and validation techniques is randomized benchmarking (RB), an important statistical tool used to characterize the performance of physical logic operations useful in quantum information processing. In this work we provide a detailed mathematical treatment of the effect of temporal noise correlations on the outcomes of RB protocols. We provide a fully analytic framework capturing the accumulation of error in RB expressed in terms of a three-dimensional random walk in "Pauli space." Using this framework we derive the probability density function describing RB outcomes (averaged over noise) for both Markovian and correlated errors, which we show is generally described by a Γ distribution with shape and scale parameters depending on the correlation structure. Long temporal correlations impart large nonvanishing variance and skew in the distribution towards high-fidelity outcomes--consistent with existing experimental data--highlighting potential finite-sampling pitfalls and the divergence of the mean RB outcome from worst-case errors in the presence of noise correlations. We use the filter-transfer function formalism to reveal the underlying reason for these differences in terms of effective coherent averaging of correlated errors in certain random sequences. We conclude by commenting on the impact of these calculations on the utility of single-metric approaches to quantum characterization, verification, and validation. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
39. Towards fully commercial, UV-compatible fiber patch cords.
- Author
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Marciniak CD, Ball HB, Hung AT, and Biercuk MJ
- Abstract
We present and analyze two pathways to produce commercial optical-fiber patch cords with stable long-term transmission in the ultraviolet (UV) at powers up to ~ 200 mW, and typical bulk transmission between 66-75 %. Commercial fiber patch cords in the UV are of great interest across a wide variety of scientific applications ranging from biology to metrology, and the lack of availability has yet to be suitably addressed. We provide a guide to producing such solarization-resistant, hydrogen-passivated, polarization-maintaining, connectorized and jacketed optical fibers compatible with demanding scientific and industrial applications. Our presentation describes the fabrication and hydrogen loading procedure in detail and presents a high-pressure vessel design, calculations of required H
2 loading times, and information on patch cord handling and the mitigation of bending sensitivities. Transmission at 313 nm is measured over many months for cumulative energy on the fiber output of > 10 kJ with no demonstrable degradation due to UV solarization, in contrast to standard uncured fibers. Polarization sensitivity and stability are characterized yielding polarization extinction ratios between 15 dB and 25 dB at 313 nm, where we find patch cords become linearly polarizing. We observe that particle deposition at the fiber facet induced by high-intensity UV exposure can (reversibly) deteriorate patch cord performance and describe a technique for nitrogen purging of fiber collimators which mitigates this phenomenon.- Published
- 2017
- Full Text
- View/download PDF
40. Frequency stabilization of a 369 nm diode laser by nonlinear spectroscopy of Ytterbium ions in a discharge.
- Author
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Lee MW, Jarratt MC, Marciniak C, and Biercuk MJ
- Abstract
We demonstrate stabilization of an ultraviolet diode laser via Doppler-free spectroscopy of Ytterbium ions in a discharge. Our technique employs polarization spectroscopy, which produces a natural dispersive lineshape whose zero-crossing is largely immune to environmental drifts, making this signal an ideal absolute frequency reference for Yb+ ion trapping experiments. We stabilize an external-cavity diode laser near 369 nm for cooling Yb+ ions, using amplitude modulated polarization spectroscopy and a commercial PID feedback system. We achieve stable, low-drift locking with a standard deviation of measured laser frequency ∼ 400 kHz over 10 minutes, limited by the instantaneous linewidth of the diode laser. These results and the simplicity of our optical setup makes our approach attractive for stabilization of laser sources in atomic physics applications.
- Published
- 2014
- Full Text
- View/download PDF
41. Optimized noise filtration through dynamical decoupling.
- Author
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Uys H, Biercuk MJ, and Bollinger JJ
- Abstract
Recent studies have shown that applying a sequence of Hahn spin-echo pulses to a qubit system at judiciously chosen intervals can, in certain noise environments, greatly improve the suppression of phase errors compared to traditional dynamical decoupling approaches. By enforcing a simple analytical condition, we obtain sets of dynamical decoupling sequences that are designed for optimized noise filtration, but are independent of the noise spectrum up to a single scaling factor set by the coherence time of the system. These sequences are tested in a model qubit system, ;{9}Be;{+} ions in a Penning trap. Our combined theoretical and experimental studies show that in high-frequency-dominated noise environments with sharp high-frequency cutoffs this approach may suppress phase errors orders of magnitude more efficiently than comparable techniques can.
- Published
- 2009
- Full Text
- View/download PDF
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