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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

SQuaD: Smart Quantum Detection for Photon Recognition and Dark Count Elimination

Quantum detectors of single photons are an essential component for quantum information processing across computing, communication and networking. Today's quantum detection system, which consists of single photon detectors, timing electronics, control and data processing software, is primarily used for counting the number of single photon detection events. However, it is largely incapable of extracting other rich physical characteristics of the detected photons, such as their wavelengths, polarization states, photon numbers, or temporal waveforms. This work, for the first time, demonstrates a smart quantum detection system, SQuaD, which integrates a field programmable gate array (FPGA) with a neural network model, and is designed to recognize the features of photons and to eliminate detector dark-count. The SQuaD is a fully integrated quantum system with high timing-resolution data acquisition, onboard multi-scale data analysis, intelligent feature recognition and extraction, and feedback-driven system control. Our \name experimentally demonstrates 1) reliable photon counting on par with the state-of-the art commercial systems; 2) high-throughput data processing for each individual detection events; 3) efficient dark count recognition and elimination; 4) up to 100% accurate feature recognition of photon wavelength and polarization. Additionally, we deploy the SQuaD to an atomic (erbium ion) photon emitter source to realize noise-free control and readout of a spin qubit in the telecom band, enabling critical advances in quantum networks and distributed quantum information processing.

Linne, Karl C. [U. Chicago (main)] (ORCID:00090009↗
DOE OSTI2017

Heralded quantum gates for atomic systems assisted by the scattering of photons off single emitters

Quantum logic gates are essential in quantum information processing. Here, we propose three heralded schemes for universal quantum gates, including the controlled-NOT, Toffoli, and Fredkin gates on atomic systems, assisted by the scattering of photons off single emitters in one-dimensional waveguides. Interestingly, our schemes can turn faulty scattering processes of photons off atoms into the detection of the photon polarization. Furthermore, auxiliary atomic qubits are not needed and only one photon medium is adopted. With current technology, we discuss the feasibility of these universal quantum gates, concluding that they are feasible and scalable in solid-state quantum systems. We provide a different method for realizing universal quantum gates, and it may be useful in quantum information processing in the future.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2010

Enhanced selectivity and efficiency of coherent population transfer via a train of pulse pairs

We propose a way to significantly enhance selectivity and efficiency of coherent population transfer in a {Lambda}-type four-level system with a closely spaced doublet in the final state by using a train of counterintuitively ordered pump-Stokes pulse pairs. Due to temporal constructive and destructive quantum interference between the sequential transitions and subsequent coherent accumulation and annihilation in the time domain, the spectral resolution of selective and perfect population transfer to either of the final states can be improved by more than one order of magnitude as compared to the conventionally widely used stimulated Raman adiabatic passage and chirped adiabatic passage techniques, which can also be well understood as a result of the formation of a comblike structure of the pulse train spectrum in the frequency domain. Moreover, an arbitrary coherent superposition between the closely separated doublet can be achieved by suitably tuning the repetition period and detuning of the laser fields. This method has potential applications in control of chemical reactions and quantum information processing.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Experimental Realization of Decoherence-Free Subspace in Neutron Interferometry

A decoherence-free subspace (DFS) is an important class of quantum-error-correcting (QEC) codes that have been proposed for fault-tolerant quantum computation. The applications of QEC techniques, however, are not limited to quantum-information processing (QIP). Here we demonstrate how QEC codes may be used to improve experimental designs of quantum devices to achieve noise suppression. In particular, neutron interferometry is used as a test bed to show the potential for adding quantum error correction to quantum measurements. We built a five-blade neutron interferometer that incorporates both a standard Mach-Zender configuration and a configuration based on a DFS. Experiments verify that the DFS interferometer is protected against low-frequency mechanical vibrations. We anticipate these improvements will increase the range of applications for matter-wave interferometry.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2023

Frequency-bin photonic quantum information

Discrete frequency modes, or bins, present a blend of opportunities and challenges for photonic quantum information processing. Frequency-bin-encoded photons are readily generated by integrated quantum light sources, naturally high-dimensional, stable in optical fiber, and massively parallelizable in a single spatial mode. Yet quantum operations on frequency-bin states require coherent and controllable multifrequency interference, making them significantly more challenging to manipulate than more traditional spatial degrees of freedom. In this mini-review, we describe recent developments that have transformed these challenges and propelled frequency bins forward. Focusing on sources, manipulation schemes, and detection approaches, we introduce the basics of frequency-bin encoding, summarize the state of the art, and speculate on the field’s next phases. Given the combined progress in integrated photonics, high-fidelity quantum gates, and proof-of-principle demonstrations, frequency-bin quantum information is poised to emerge from the lab and leave its mark on practical quantum information processing—particularly in networking where frequency bins offer unique tools for multiplexing, interconnects, and high-dimensional communications.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2012

Ion-Photon Quantum Interface: Entanglement Engineering

Distributed quantum information processing requires a reliable quantum memory and a faithful carrier of quantum information. Trapped ion qubits are the leading realization for quantum information storage, and photonic qubits are the natural choice for the transport of quantum information. The capability to entangle photons with trapped ions in a highly efficient (scalable) fashion is an important achievement. Here, we leverage the active and successful development of micro-fabricated semiconductor ion traps at the Sandia National Laboratory MESA facility, and integrate micro optical components. Compared to current efforts in academic settings combining macro-sized ion traps and optics, a micro device will result in the dramatically increased speed and fidelity of ion-trap based quantum networking protocols. Integrating smaller components will directly allow for a stronger quantum coherent interface between a single trapped ion and a single photon. If successful, this technology could lead to new demonstrations of fundamental physics properties and would open new avenues for scalable quantum networking architectures.

Moehring, David Lynn↗
DOE OSTI2025

On-chip frequency-bin quantum photonics

Abstract Frequency-bin encoding furnishes a compelling pathway for quantum information processing systems compatible with established lightwave infrastructures based on fiber-optic transmission and wavelength-division multiplexing. Yet although significant progress has been realized in proof-of-principle tabletop demonstrations, ranging from arbitrary single-qubit gates to controllable multiphoton interference, challenges in scaling frequency-bin processors to larger systems remain. In this Perspective, we highlight recent advances at the intersection of frequency-bin encoding and integrated photonics that are fundamentally transforming the outlook for scalable frequency-based quantum information. Focusing specifically on results on sources, state manipulation, and hyperentanglement, we envision a possible future in which on-chip frequency-bin circuits fulfill critical roles in quantum information processing, particularly in communications and networking.

electro-optic modulators↗
DOE OSTI2015

Loading an Equidistant Ion Chain in a Ring Shaped Surface Trap and Anomalous Heating Studies with a High Optical Access Trap

Microfabricated segmented surface ion traps are one viable avenue to scalable quantum information processing. At Sandia National Laboratories we design, fabricate, and characterize such traps. Our unique fabrication capabilities allow us to design traps that facilitate tasks beyond quantum information processing. The design and performance of a trap with a target capability of storing hundreds of equally spaced ions on a ring is described. Such a device could aid experimental studies of phenomena as diverse as Hawking radiation, quantum phase transitions, and the Aharonov - Bohm effect. The fabricated device is demonstrated to hold a ~ 400 ion circular crystal, with 9 μm average spacing between ions. The task is accomplished by first characterizing undesired electric fields in the trapping volume and then designing and applying an electric field that substantially reduces the undesired fields. In addition, experimental efforts are described to reduce the motional heating rates in a surface trap by low energy in situ argon plasma treatment that reduces the amount of surface contaminants. The experiment explores the premise that carbonaceous compounds present on the surface contribute to the anomalous heating of secular motion modes in surface traps. This is a research area of fundamental interest to the ion trapping community, as heating adversely affects coherence and thus gate fidelity. The device used provides high optical laser access, substantially reducing scatter from the surface, and thus charging that may lead to excess micromotion. Heating rates for different axial mode frequencies are compared before and after plasma treatment. The presence of a carbon source near the plasma prevents making a conclusion on the observed absence of change in heating rates.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Two local observables are sufficient to characterize maximally entangled states of N qubits

Maximally entangled states (MES) represent a valuable resource in quantum information processing. In N-qubit systems the MES are N-GHZ states [i.e., the collection of |GHZ{sub N}>=(1/{radical}(2))(|00...0>+|11...1>)] and its local unitary (LU) equivalences. While it is well known that such states are uniquely stabilized by N commuting observables, in this article we consider the minimum number of noncommuting observables needed to characterize an N-qubit MES as the unique common eigenstate. Here, we prove, rather surprisingly, that in this general case any N-GHZ state can be uniquely stabilized by only two observables. Thus, for the task of MES certification, only two correlated measurements are required with each party observing the spin of his or her system along one of two directions.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

High Mobility and Electrostatics in GeSn Quantum Wells With SiGeSn Barriers

GeSn is an emerging material with potential applications in next‐generation integrated optoelectronics and quantum information processing. While GeSn/SiGeSn quantum wells exhibit promising optical properties, their electrical transport characteristics and governing electrostatics in gated structures remain unexplored. Heterostructure field‐effect transistors are fabricated using GeSn/SiGeSn quantum wells and electronic transport properties of 2D holes are characterized. At 2 K, heterostructure field‐effect transistors with well/barrier compositions of Ge 0.945 Sn 0.055 /Si 0.03 Ge 0.93 Sn 0.04 and Ge 0.9 Sn 0.1 /Si 0.017 Ge 0.927 Sn 0.056 , show peak mobilities of 9000 and 19 000 cm 2 /Vs, respectively, the latter setting a record for the highest mobility reported for GeSn quantum wells with a Sn concentration around 6 % or greater. Remarkably, at low carrier densities, devices with a SiGeSn barrier exhibit mobilities several times higher than previously reported for GeSn quantum wells with a Ge barrier. This higher mobility contrasts with the expectation that alloy scattering from the barrier would reduce carrier mobility. Two mechanisms based on atom probe tomography data analyses are proposed: i) unintentionally improved SiGeSn/GeSn interface and/or ii) reduced alloy scattering from short‐range order. Significant current–voltage hysteresis is observed, with the effective threshold gate voltage shifting by more than 5 V, attributed to non‐equilibrium trapped charge at various interfaces within the SiGeSn heterostructure.

GeSn↗
DOE OSTI2015

A comparative study of concurrence and negativity of general three-level quantum systems of two particles

Quantum entanglement is at the heart of quantum information processing. Ordering the quantum systems due to their entanglement is a popular problem of the field. For two level (qubit) systems of two particles, state ordering has been studied with respect to well-known entanglement measures such as Concurrence, Negativity and Relative Entropy of Entanglement (REE) [1-5]. In this work, we study the state ordering of the three-level quantum systems of two particles with respect to Concurrence and Negativity. In particular, constructing 10K random states and calculating their Concurrences and Negativities, we obtain the orderings of the states and present our results which are interesting when compared to that of two-level systems.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Coherent electron-spin-resonance manipulation of three individual spins in a triple quantum dot

Quantum dot arrays provide a promising platform for quantum information processing. For universal quantum simulation and computation, one central issue is to demonstrate the exhaustive controllability of quantum states. Here, we report the addressable manipulation of three single electron spins in a triple quantum dot using a technique combining electron-spin-resonance and a micro-magnet. The micro-magnet makes the local Zeeman field difference between neighboring spins much larger than the nuclear field fluctuation, which ensures the addressable driving of electron-spin-resonance by shifting the resonance condition for each spin. We observe distinct coherent Rabi oscillations for three spins in a semiconductor triple quantum dot with up to 25 MHz spin rotation frequencies. This individual manipulation over three spins enables us to arbitrarily change the magnetic spin quantum number of the three spin system, and thus to operate a triple-dot device as a three-qubit system in combination with the existing technique of exchange operations among three spins.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2013

Scaling the Ion Trap Quantum Processor

Trapped atomic ions are standards for quantum information processing, serving as quantum memories, hosts of quantum gates in quantum computers and simulators, and nodes of quantum communication networks. Quantum bits based on trapped ions enjoy a rare combination of attributes: They have exquisite coherence properties, they can be prepared and measured with nearly 100% efficiency, and they are readily entangled with each other through the Coulomb interaction or remote photonic interconnects. The outstanding challenge is the scaling of trapped ions to hundreds or thousands of qubits and beyond, at which scale quantum processors can outperform their classical counterparts in certain applications. We review the latest progress and prospects in that effort, with the promise of advanced architectures and new technologies, such as microfabricated ion traps and integrated photonics.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Semi-device-independent bounds on entanglement

Detection and quantification of entanglement in quantum resources are two key steps in the implementation of various quantum-information processing tasks. Here, we show that Bell-type inequalities are not only useful in verifying the presence of entanglement but can also be used to bound the entanglement of the underlying physical system. Our main tool consists of a family of Clauser-Horne-like Bell inequalities that cannot be violated maximally by any finite-dimensional maximally entangled state. Using these inequalities, we demonstrate the explicit construction of both lower and upper bounds on the concurrence for two-qubit states. The fact that these bounds arise from Bell-type inequalities also allows them to be obtained in a semi-device-independent manner, that is, with assumption of the dimension of the Hilbert space but without resorting to any knowledge of the actual measurements being performed on the individual subsystems.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2010

Entanglement generation of nitrogen-vacancy centers via coupling to nanometer-sized resonators and a superconducting interference device

We present a potential scheme to entangle negatively charged nitrogen-vacancy (N-V) centers in distance using nanomechanical resonators (NAMRs) and a common superconducting quantum interference device (SQUID). By virtually exciting the vibrational modes of the NAMRs, we show the effective coupling between the N-V centers and the SQUID, which is a promising step toward large-sized quantum-information processing with separate N-V centers.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Characterization of a fiber-based source of heralded single photons

Starting from the derived expression of the Bogoliubov transformation for a broadband pulsed pump, we theoretically characterize the heralded single-photon source, which is based on the signal and idler photon pairs produced in optical fiber via spontaneous four-wave mixing by a pulsed pump. The second-order intensity correlation function, heralding efficiency, indistinguishability, and brightness of the heralded single photons as a function of source parameters, are analyzed and discussed. The validity of the theoretical analysis and calculations are confirmed by the experimental results. The investigations are useful for optimizing the source parameters and for developing a single-photon source suitable for quantum-information processing.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2010

Multifrequency spin resonance in diamond

Magnetic resonance techniques provide a powerful tool for controlling spin systems, with applications ranging from quantum information processing to medical imaging. Nevertheless, the behavior of a spin system under strong excitation remains a rich dynamical problem. In this paper, we examine spin resonance of the nitrogen-vacancy center in diamond under conditions outside the regime where the usual rotating-wave approximation applies, focusing on effects of multifrequency excitation and excitation with orientation parallel to the spin quantization axis. Strong-field phenomena such as multiphoton transitions and coherent destruction of tunneling are observed in the spectra and analyzed via numerical and analytic theory. In addition to illustrating the response of a spin system to strong multifrequency excitation, these observations may inform techniques for manipulating electron-nuclear spin quantum registers.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗