Electric field control of interaction between magnons and quantum spin defects
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Solanki, Abhishek B.↗
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Results for “Quantum control”
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Investigation of Optimizations for FPGA-based Controls Hardware for Experiments using Superconducting Quantum Computing Systems
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Scalable control systems for trapped-ion quantum computing
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Stick, Daniel Lynn↗
Feedback-based calibration for tuning and drift control of a trapped-ion quantum processor
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Miller, Nathan Eli↗
Adiabatically-controlled two-qubit gates using quantum dot hybrid qubits.
Abstract not provided.
Frees, Adam↗
Adiabatically-controlled two-qubit gates using quantum dot hybrid qubits.
Abstract not provided.
Frees, Adam↗
Digital quantum simulation of molecular dynamics and control.
Abstract not provided.
Magann, Alicia Bette↗
TQEA: Temporal Quantum Error Analysis
For the last few years quantum computers have captured researchers’ interest in solving complicated problems in finance, chemistry, machine learning, and many other NP problems. Quantum computing benefits from parallel computation, entanglement, and calculation speedup compared to classical computing. Even though the operations and number of qubits in quantum computers are limited, previous research showed that using quantum computers can be beneficial. These benefits gained researchers’ interest to work on the improvement of quantum computers and overcome the limitations by building more advanced quantum computers with fault tolerance capability, more physical qubits, and better operational gates. In practice, Quantum applications would be translated into Quantum Circuits and each circuit can contain one or many entanglements (s), single qubits operations, and readouts. The importance of running Quantum applications with controlled errors or without errors is critical to the desired result from Quantum readout. In this paper, we study the characteristics of superconducting quantum machines along with the previously proposed methods of Quantum error detection/correction and in order to build a better error model we propose a temporal method for analyzing the the behavior of qubits errors (T1 and T2), frequency of operation, entanglement errors, and readout errors. In order to detect and predict the behavior of each machine, we use simple exponential smoothing analysis on heuristic calibration data. Finally, based on observation, we show that based on frequency, qubits, readout and single operation errors we can build a temporal based model to study and predict the outcome of runs on each Quantum machine.
Baheri, Betis↗
Precision requirements for spin-echo-based quantum memories
Spin-echo techniques are essential for achieving long coherence times in solid-state quantum memories for light because of inhomogeneous broadening of the spin transitions. It has been suggested that unrealistic levels of precision for the radio-frequency control pulses would be necessary for successful decoherence control at the quantum level. Here we study the effects of pulse imperfections in detail, using both a semiclassical and a fully quantum-mechanical approach. Our results show that high efficiencies and low noise-to-signal ratios can be achieved for the quantum memories in the single-photon regime for realistic levels of control pulse precision. We also analyze errors due to imperfect initial-state preparation (optical pumping), showing that they are likely to be more important than control pulse errors in many practical circumstances. These results are crucial for future developments of solid-state quantum memories.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Nanodiamond-based nanostructures for coupling nitrogen-vacancy centres to metal nanoparticles and semiconductor quantum dots
The ability to control the interaction between nitrogen-vacancy centres in diamond and photonic and/or broadband plasmonic nanostructures is crucial for the development of solid-state quantum devices with optimum performance. However, existing methods typically employ top-down fabrication, which restrict scalable and feasible manipulation of nitrogen-vacancy centres. Here, we develop a general bottom-up approach to fabricate an emerging class of freestanding nanodiamond-based hybrid nanostructures with external functional units of either plasmonic nanoparticles or excitonic quantum dots. Precise control of the structural parameters ( including size, composition, coverage and spacing of the external functional units) is achieved, representing a pre-requisite for exploring the underlying physics. Fine tuning of the emission characteristics through structural regulation is demonstrated by performing single-particle optical studies. Lastly, this study opens a rich toolbox to tailor properties of quantum emitters, which can facilitate design guidelines for devices based on nitrogen vacancy centres that use these freestanding hybrid nanostructures as building blocks.
77 NANOSCIENCE AND NANOTECHNOLOGY↗
Demonstrating the Potential of Adaptive LMS Filtering on FPGA-Based Qubit Control Platforms for Improved Qubit Readout in 2D and 3D Quantum Processing Units
Advancements in quantum computing underscore the critical need for sophisticated qubit readout techniques to accurately discern quantum states. This abstract presents our research intended for optimizing readout pulse fidelity for 2D and 3D Quantum Processing Units (QPUs), the latter coupled with Superconducting Radio Frequency (SRF) cavities. Focusing specifically on the application of the Least Mean Squares (LMS) adaptive filtering algorithm, we explore its integration into the FPGA-based control systems to enhance the accuracy and efficiency of qubit state detection by improving Signal-to-Noise Ratio (SNR). Implementing the LMS algorithm on the Zynq UltraScale+ RFSoC Gen 3 devices (RFSoC 4x2 FPGA and ZCU216 FPGA) using the Quantum Instrumentation Control Kit (QICK) open-source platform, we aim to dynamically test and adjust the filtering parameters in real-time to characterize and adapt to the noise profile presented in quantum computing readout signals. Our preliminary results demonstrate the LMS filter's capability to maintain high readout accuracy while efficiently managing FPGA resources. These findings are expected to contribute to developing more reliable and scalable quantum computing architectures, highlighting the pivotal role of adaptive signal processing in quantum technology advancements.
Johnson, Hans↗
Demonstrating the Potential of Adaptive LMS Filtering on FPGA-Based Qubit Control Platforms for Improved Qubit Readout in 2D and 3D Quantum Processing Units
Advancements in quantum computing underscore the critical need for sophisticated qubit readout techniques to accurately discern quantum states. This abstract presents our research intended for optimizing readout pulse fidelity for 2D and 3D Quantum Processing Units (QPUs), the latter coupled with Superconducting Radio Frequency (SRF) cavities. Focusing specifically on the application of the Least Mean Squares (LMS) adaptive filtering algorithm, we explore its integration into the FPGA-based control systems to enhance the accuracy and efficiency of qubit state detection by improving Signal-to-Noise Ratio (SNR). Implementing the LMS algorithm on the Zynq UltraScale+ RFSoC Gen 3 devices (RFSoC 4x2 FPGA and ZCU216 FPGA) using the Quantum Instrumentation Control Kit (QICK) open-source platform, we aim to dynamically test and adjust the filtering parameters in real-time to characterize and adapt to the noise profile presented in quantum computing readout signals. Our preliminary results demonstrate the LMS filter's capability to maintain high readout accuracy while efficiently managing FPGA resources. These findings are expected to contribute to developing more reliable and scalable quantum computing architectures, highlighting the pivotal role of adaptive signal processing in quantum technology advancements.
Johnson, Hans↗
Efficient synthesis of quantum gates on a three-spin system with triangle topology
Experiments in coherent nuclear and electron magnetic resonance and optical spectroscopy correspond to control of quantum-mechanical ensembles, guiding them from initial states to target states by unitary transformations. The control inputs (pulse sequences) that accomplish these unitary transformations should take as little time as possible so as to minimize the effects of relaxation and decoherence, and to optimize the sensitivity of the experiments. Here, we give an efficient synthesis of a class of unitary transformations on a three coupled spin-(1/2) system with equal Ising coupling strengths. We show a significant time saving compared with conventional methods.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Plasmonic Control of Radiation and Absorption Processes in Semiconductor Quantum Dots
This document reviews a research program funded by the DOE Office of Science, which has been focused on the control of radiation and absorption processes in semiconductor photonic materials (including III-nitride quantum wells and quantum dots), through the use of specially designed metallic nanoparticles (NPs). By virtue of their strongly confined plasmonic resonances (i.e., collective oscillations of the electron gas), these nanostructures can concentrate incident radiation into sub-wavelength “hot spots” of highly enhanced field intensity, thereby increasing optical absorption by suitably positioned absorbers. By reciprocity, the same NPs can also dramatically increase the spontaneous emission rate of radiating dipoles located within their hot spots. The NPs can therefore be used as optical antennas to enhance the radiation output of the underlying active material and at the same time control the far-field pattern of the emitted light. The key accomplishments of the project include the demonstration of highly enhanced light emission efficiency as well as plasmonic collimation and beaming along geometrically tunable directions, using a variety of plasmonic excitations. Initial results showing the reverse functionality (i.e., plasmonic unidirectional absorption and photodetection) have also been generated with similar systems. Furthermore, a new paradigm for the near-field control of light emission has been introduced through rigorous theoretical studies, based on the use of gradient metasurfaces (i.e., optical nanoantenna arrays with spatially varying shape, size, and/or orientation). These activities have been complemented by materials development efforts aimed at the synthesis of suitable light-emitting samples by molecular beam epitaxy. In the course of these efforts, a novel technique for the growth of III-nitride quantum dots has also been developed (droplet heteroepitaxy), with several potential advantages in terms of compositional and geometrical control. The results of these studies provide fundamental new understanding of optical processes at the nanoscale, including near-field energy transfer between quantum emitters and photonic nanostructures, dissipation phenomena of plasmonic excitations, and radiation from nanoantennas. Furthermore, they may open the way to entirely new device concepts and applications, in a broad range of disciplines including optoelectronics, sensing, spectroscopy, photovoltaics, and quantum information science. A specific application of particularly strong relevance to the DOE mission is the development of energy efficient LED active materials for solid-state lighting, based on plasmonic enhancement effects.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Concluding remarks: Directing and controlling materials and molecules
Controlling materials, especially quantum materials, is a key goal of physical science. Biology provides inspiration for control of materials and molecules via feedback loops.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Studies of Novel Quantum Phenomena in Ruthenates
Strongly correlated oxides have been the subject of intense study in contemporary condensed matter physics, and perovskite ruthenates (Sr,Ca)n+1RunO3n+1 have become a new focus in this field. One of important characteristics of ruthenates is that both lattice and orbital degrees of freedom are active and are strongly coupled to charge and spin degrees of freedom. Such a complex interplay of multiple degrees of freedom causes the properties of ruthenates to exhibit a gigantic response to external stimuli under certain circumstances. Magnetic field, pressure, and chemical composition all have been demonstrated to be effective in inducing electronic/magnetic phase transitions in ruthenates. Therefore, ruthenates are ideal candidates for searching for novel quantum phenomena through controlling external parameters. The objective of this project is to search for novel quantum phenomena in ruthenate materials using high-quality single crystals grown by the floating-zone technique, and investigate the underlying physics. The following summarizes our accomplishments. We have focused on trilayered Sr4Ru3O10 and bilayered (Ca1-xSrx)3Ru2O7. We have succeeded in growing high-quality single crystals of these materials using the floating-zone technique and performed systematic studies on their electronic and magnetic properties through a variety of measurements, including resistivity, Hall coefficient, angle-resolved magnetoresistivity, Hall probe microscopy, and specific heat. We have also studied microscopic magnetic properties for some of these materials using neutron scattering in collaboration with Los Alamos National Laboratory. We have observed a number of unusual exotic quantum phenomena through these studies, such as an orbital selective metamagnetic transition, bulk spin valve effect, and a heavy-mass nearly ferromagnetic state with a surprisingly large Wilson ratio. Our work has also revealed underlying physics of these exotic phenomena. Exotic phenomena of correlated electron has been among central topics of contempary condensed matter physics. Ultrfast phase transitions accompanied by switching of conductivity or magnetization in stronly correlated materials are believed to be promising in developing next generation of transistors. Our work on layered ruthenates has remarkably advanced our understanding of how the exotic phenomena of correlated electrons is governed by the complex interplay between charge, spin, lattice and orbital degrees of freedom. In addition to studies on ruthenates, we have also expanded our research to the emerging field of Fe-based superconductors, focusing on the iron chalcogenide Fe1+y(Te1-xSex) superconductor system. We first studied the superconductivity of this alloy system following the discovery of superconductivity in FeSe using polycrystalline samples. Later, we successfuly grew high-quality single crystals of these materials. Using these single crystals, we have determined the magnetic structure of the parent compound Fe1+yTe, observed spin resonance of superconducting state in optimally doped samples, and established a phase diagram. Our work has produced an important impact in this burgeoning field. The PI presented an invited talk on this topic at APS March meeting in 2010. We have published 19 papers in these two areas (one in Nature materials, five in Physical Review Letters, and nine in Physical Review B) and submitted two (see the list of publications attached below).
36 MATERIALS SCIENCE↗
Simulation and analysis of grating-integrated quantum dot infrared detectors for spectral response control and performance enhancement
We propose and analyze a novel detector structure for pixel-level multispectral infrared imaging. More specifically, we investigate the device performance of a grating-integrated quantum dots-in-a-well photodetector under backside illumination. Our design uses 1-dimensional grating patterns fabricated directly on a semiconductor contact layer and, thus, adds a minimal amount of additional effort to conventional detector fabrication flows. We show that we can gain wide-range control of spectral response as well as large overall detection enhancement by adjusting grating parameters. For small grating periods, the spectral responsivity gradually changes with parameters. We explain this spectral tuning using the Fabry–Perot resonance and effective medium theory. For larger grating periods, the responsivity spectra get complicated due to increased diffraction into the active region, but we find that we can obtain large enhancement of the overall detector performance. In our design, the spectral tuning range can be larger than 1 μm, and, compared to the unpatterned detector, the detection enhancement can be greater than 92% and 148% for parallel and perpendicular polarizations. Our work can pave the way for practical, easy-to-fabricate detectors, which are highly useful for many infrared imaging applications.
77 NANOSCIENCE AND NANOTECHNOLOGY↗