Bulletin of the American Physical Society
APS March Meeting 2019
Volume 64, Number 2
Monday–Friday, March 4–8, 2019; Boston, Massachusetts
Session P28: Quantum Measurement and Sensing II |
Hide Abstracts |
Sponsoring Units: DQI Chair: Bradley Moores, University of Colorado, Boulder Room: BCEC 161 |
Wednesday, March 6, 2019 2:30PM - 2:42PM |
P28.00001: Imaging Vortex Dynamics in High-Tc Superconductors using Ensemble Nitrogen Vacancy (NV) Centers in Diamond Aditya Malusare, Sumiran Pujari, Shamashis Sengupta, Kasturi Saha Nitrogen-Vacancy (NV) centers are excellent quantum sensors due to their long spin-coherence time and ultrahigh magnetic field sensitivity. An ensemble of NVs can be used for vector magnetometry of high-Tc superconductors to investigate several processes of interest with nanometer resolution over a wide field. We study the feasibility of measuring vortex dynamics, which plays a pivotal role in understanding the mechanisms underlying superconductivity. In this work, we make a fully functional simulation of a thin-film type-II superconductor with properties similar to materials like BSCCO or YBCO and theoretically demonstrate a scheme for mapping vortices in real time. Utilizing the capabilities of the NV center as a high-speed imaging sensor, we can probe the dynamics of vortex pinning and nucleation. Effects of impurities, thermal fluctuations, varying thickness and other defects can be examined through NVs with nanometer resolution as shown in our simulations as well. |
Wednesday, March 6, 2019 2:42PM - 2:54PM |
P28.00002: Zappe Photon Upconverters for Quantum Measurements of Low-Frequency Electrical Resonators, Part I: Theory Saptarshi Chaudhuri, Hsiao-Mei Cho, Carl Dawson, Peter W. Graham, Rachel Gruenke, Stephen Kuenstner, Dale Li, Arran TJ Phipps, Charles Titus, Betty Young, Cyndia Yu, Kent David Irwin We present the Zappe Photon Upconverter (ZPU), a Josephson-junction-based readout amplifier for performing quantum measurements on lumped-element LC resonators (100 Hz-300 MHz). The ZPU exploits the symmetries of a three-junction Zappe interferometer embedded inside a microwave resonator. The Zappe element acts as a flux-variable inductor, cleanly implementing a three-wave-mixing interaction between the low-frequency resonator at the flux input and the high-frequency (~6 GHz) microwave resonator. The interaction is analogous to the interaction between resonators in electromechanical and optomechanical systems. We establish protocols for flux sensing at the Standard Quantum Limit (SQL), as well as backaction evasion techniques that permit measurements below the SQL. We discuss applications of ZPUs, in particular axion dark matter searches, where these devices can enable scan rate enhancements of orders of magnitude. |
Wednesday, March 6, 2019 2:54PM - 3:06PM |
P28.00003: Zappe Photon Upconverters for Quantum Measurements of Low-Frequency Electrical Resonators, Part II: Implementation of the Prototype Stephen Kuenstner, Saptarshi Chaudhuri, Hsiao-Mei Cho, Carl Dawson, Peter W. Graham, Rachel Gruenke, Dale Li, Arran TJ Phipps, Charles Titus, Betty Young, Cyndia Yu, Kent David Irwin We describe progress towards the first Zappe Photon Upconverter (ZPU), a Josephson-junction-based device capable of performing quantum mechanical readout protocols on low-frequency, lumped-element electromagnetic resonators. The prototype ZPU is being constructed using techniques similar to those used in superconducting transmon qubits, where the Josephson device is connected to a lithographed antenna immersed in the electromagnetic field of a three-dimensional microwave cavity. We describe the constraints on the circuit design and propose targets for the component values. We also present measurements of the quality factor of the superconducting microwave cavity designed for use with the first-generation ZPU, numerical modeling of the circuit parameters, and projections of the sensitivity enhancement available from backaction evading measurements using a prototype ZPU. |
Wednesday, March 6, 2019 3:06PM - 3:18PM |
P28.00004: Optical sensing of biological processes with nitrogen-vacancy centers in nanodiamonds Changhao Li, Dominika Lyzwa, Mohammad Kohandel, Paola Cappellaro Nitrogen-vacancy (NV) centers in nanodiamonds are very attractive probes for sensing chemical reactions and biological processes. Their relaxation times are especially sensitive to the surrounding environment and can be probed with an all-optical protocol. To induce strong variations in the relaxation, the nanodiamonds can be brought in proximity to Gadolinium (Gd) ions which are strongly paramagnetic and can effectively quench the NV relaxation time. By optically monitoring the relaxation, it is possible to observe chemical and biological processes that affect the distance between Gd and nanodiamond. Here we first directly cover the nanodiamonds with chelated Gd and characterize the quenching effect for different Gd concentrations on an ensemble of nanodiamonds with an average diameter of around 20 nm. We will further show how the nanodiamonds can be connected with Gd via a cleavable peptide sequence. Specific enzymes, released during apoptosis, can cut the connection thus separating NVs from Gd and decreasing the relaxation rate. The nanodiamond sensors have the potential to be used simultaneously as drug delivery probes in addition to optical sensing, hence they might allow for monitoring chemotherapy. |
Wednesday, March 6, 2019 3:18PM - 3:30PM |
P28.00005: High Sensitivity Magnetometry with a Fibre-coupled Diamond Sensor Rajesh Patel, Angelo Frangeskou, Guy Stimpson, Eleanor Nichols, William Thornley, Ben G Breeze, Ben Green, Shinobu Onoda, Junichi Isoya, Gavin Morley The negatively charged nitrogen-vacancy (NV) centre in diamond is one of the most studied solid-state defects because it has spin states that can be initialised and detected optically at room temperature [1]. A key technological development is the use of an ensemble of these defects for applications in high sensitivity magnetometry [2] which may lead to the development of medical devices for techniques such as magnetocardiography [3]. We present a fiber-coupled system which aims to detect the magnetic fields produced by electrical currents in the heart. |
Wednesday, March 6, 2019 3:30PM - 3:42PM |
P28.00006: Dopant-Free Single Electron Pumps for Quantum Metrology Francois Sfigakis, Brandon Buonacorsi, Arjun Shetty, Chris Deimert, Alan Tam, HoSung Kim, Zbig Wasilewski, Niels Ubbelohde, Frank Hohls, Jonathan D Baugh At low temperature, we have observed low-disorder quantized conductance in quantum wires fabricated in dopant-free GaAs/AlGaAs two-dimensional electron gases (2DEG) with mobilities up to 7x106 cm2/Vs (at 2.9x1011 /cm2), with a 1D subband energy level spacing that can be tuned from 1 meV to more than 5 meV on individual devices. The absence of (intentional) dopants produces an environment with ultra low disorder [1] and very little charge noise [2]. Single electron pumps [3,4] were fabricated and measured at 1 GHz, with up to 3 quantized current plateaus observed. Thus, dopant-free quantum wires provide a unique platform to investigate electron-electron interactions, and could offer a path towards single electron pumps suitable for a quantum current standard [5]. |
Wednesday, March 6, 2019 3:42PM - 3:54PM |
P28.00007: Imaging Viscous Flow of Hydrodynamic Electron Fluid in Graphene with Nitrogen Vacancy Centers in Diamond Mark Ku, Tony Zhou, Qing Li, Young Jae Shin, Jing Shi, Claire Burch, Huiliang Zhang, Francesco Casola, Kenji Watanabe, Takashi Taniguchi, Philip Kim, Amir Yacoby, Ronald L Walsworth Collective behavior due to strong electron-electron interactions can lead to transport resembling that of a hydrodynamic fluid. Novel flow patterns, for example parabolic velocity profile known as the Poiseuille flow, arise due to viscosity in such electron fluids. In this work, we directly observe viscous Poiseuille flow in hBN-encapsulated graphene channels via imaging the associated stray magnetic field with nitrogen-vacancy (NV) centers in diamond. With wide-field magnetic imaging, we obtain diffraction-limited 2D image of the stray field generated by current flow in a graphene device on a diamond surface. The measured current density across the channel strongly deviates from the profile of a uniform flow and instead matches that of a viscous fluid. We then employ scanning NV microscopy to image the stray field with ~50 nm resolution. As a benchmark, we demonstrate the ability to image the uniform Ohmic flow in a thin metallic wire. In the case of a graphene channel, we observe a parabolic current profile corresponding to viscous Poiseuille flow. Our measurement establishes the viscous flow of a hydrodynamic electron fluid in graphene at room temperature. |
Wednesday, March 6, 2019 3:54PM - 4:06PM |
P28.00008: Imaging the local charge environment of nitrogen-vacancy centers in diamond Thomas Mittiga, Satcher Hsieh, Chong Zu, Bryce H Kobrin, Francisco Machado, Prabudhya Bhattacharyya, Nicholas Z Rui, Andrey Jarmola, Soonwon Choi, Dmitry Budker, Norman Yao Characterizing the local internal environment surrounding solid-state spin defects is crucial to harnessing them as nanoscale sensors of external fields. This is especially germane to the case of defect ensembles which can exhibit a complex interplay between interactions, internal fields and lattice strain. In this talk, we demonstrate that local electric fields dominate the magnetic resonance behavior of ensembles of nitrogen-vacancy (NV) centersin diamond at low magnetic field. We introduce a microscopic model that quantitatively captures the observed spectra for samples with NV concentrations spanning over two orders of magnitude. Motivated by this understanding, we present the implementation of a novel method for the nanoscale localization of individual charges within the diamond lattice. |
Wednesday, March 6, 2019 4:06PM - 4:18PM |
P28.00009: Spatial noise filtering through new error-correcting codes for quantum sensing David Layden, Sisi Zhou, Liang Jiang, Paola Cappellaro Quantum systems can be used to measure various quantities in their environment with high precision. Often, however, their sensitivity is limited by the decohering effects of this same environment. Dynamical decoupling schemes are widely used to filter environmental noise from signals, but their performance is limited by the spectral properties of the signal and noise at hand. Quantum error correction schemes have therefore emerged as a complementary technique without the same limitations. To date, however, they have failed to correct the dominant noise type in many quantum sensors, which couples to each qubit in a sensor in the same way as the signal. We show how quantum error correction can correct for such noise, which dynamical decoupling can only partially address. Whereas dynamical decoupling exploits temporal noise correlations in signal and noise, our scheme exploits spatial correlations. To this end, we introduce a new family of quantum error-correcting codes for sensing, which are both application- and hardware-adapted. |
Wednesday, March 6, 2019 4:18PM - 4:30PM |
P28.00010: Continuous error correction for quantum metrology Shengshi Pang, Yi-Cong Zheng, Todd Brun, Andrew N Jordan Protecting the information in quantum metrology by quantum error correction has been studied intensively in recent years. The usual assumption in quantum error correction is that the syndrome measurements and correction operations are done frequently enough so that errors generated by the noise are correctable with high probability. Here, we analyze how the rate of continuous-time quantum error correction affects quantum metrology. We show that if the rate of error correction is finite, the Heisenberg limit in quantum metrology can only be sustained for a finite period. Moreover, in contrast to quantum metrology without noise (or with sufficiently fast quantum error correction), a longer evolution time does not always produce more information. There exists an optimal time at which the Fisher information reaches the maximum. We use the simple three-qubit bit-flip code to illustrate this result. |
Wednesday, March 6, 2019 4:30PM - 4:42PM |
P28.00011: Optical hyerpolarization in nanodiamonds: towards quantum-enhanced NMR/MRI Ashok Ajoy, Raffi Nazaryan, Xudong Lv, Kristina Liu, Emanuel Druga, Jeffrey A Reimer, Carlos A. Meriles, Alexander Pines Atom-like defect center spins in wide bandgap materials, such as Nitrogen Vacancy (NV) center spins in diamond, are compelling platforms for the optical dynamic nuclear polarization (DNP) of nuclear spins. NV electronic spins can be optically polarized at room temperature, and this polarization potentially transferred to external nuclei to hyperpolarize them to levels far in excess of Boltzmann levels. Nanodiamond powder is particularly attractive in this quest: they have large surface areas (>7m2/g for 100nm particles), and one could arrange for a close physical contact between the polarized NVs and external nuclear spins. |
Wednesday, March 6, 2019 4:42PM - 4:54PM |
P28.00012: Optically hyperpolarized Nano-Diamond MRI at Room Temperature Xudong Lv, Emanuel Druga, Raffi Nazaryan, Tommy McKnelly, Alexander Pines, Ashok Ajoy, Jeffrey Walton Diamond nano-particles with surface functionalization nanoparticles for biomedical applications such as targeting, sub-cellular tracking, and non-toxic therapy [1]. The versatility of nano-diamond has motivated the development of new diamond-based imaging agents that will ‘light up’ under MRI to produce a bright field contrast image. Conventional Dynamic Nuclear Polarization mechanism which has been successfully demonstrated in diamond to hyperpolarize 13C nuclei, has to rely on high fields and cryogenic temperatures. Here we demonstrate a room temperature hyperpolarized nano-diamond 13C imaging with an enhancement of ~600 against 7T thermal polarization[2]. We were also able to achieve back ground suppression in magnetic resonance imaging with the ability of on demand controlling the sign of the hyperpolarization signal. Furthermore, combing both MRI and optical imaging of powder diamond, we present a new dual-modality nano-diamond imaging approach with orders of magnitude SNR enhancement. |
Wednesday, March 6, 2019 4:54PM - 5:06PM |
P28.00013: Environment-assisted quantum sensing with entangled electronic spins in diamond Won Kyu Calvin Sun, Alexandre Cooper, Jean-Christophe Jaskula, Paola Cappellaro Intuitively, enlarging a quantum system by the addition of controllable qubits should only enhance—not decrease—its performance: in other words, any extra qubit should prove a resource. For quantum metrology, the transition from N=1 to N=2 qubits seems especially good for both promised improvement in sensitivity—via N-fold faster phase accumulation—and in readout—via quantum non-demolition measurements. This transition is further motivated in solid-state spin systems that inevitably host a decohering spin bath: its partial conversion into resources simultaneously reduces its size. Thus, utilizing a single nitrogen-vacancy (NV) center and a nearby electron spin (X) in diamond, we explore this question by comparing the performance of N=1 (NV) and N=2 (NV + X) register in ac magnetometry. We find experimentally the ostensible benefits of the resource can be overshadowed by its very cost: namely the increased complexity to perform the same task—resulting in decreased control fidelity and duty cycle—and sensitivity to noise—resulting in decreased dynamic range. We analytically confirm these results and find a parameter space in which the bath qubit will prove a resource. Extending this work for few-qubit algorithms should aid designs of small-scale registers with a quantum advantage. |
Wednesday, March 6, 2019 5:06PM - 5:18PM |
P28.00014: Nanoscale mechanical sensing at ambient conditions Chufeng Liu, Kangwei Xia, Weng Hang Leong, Zhiyuan Yang, Quan Li, Ren-Bao Liu Negative charge nitrogen vacancy center in diamond (NV center) has attracted huge interest due to its unique spin properties even at room temperature. Its spin state could be optically addressed, manipulated and readout with excellent photo stability. Meanwhile, NV center is sensitive to many parameters, such as magnetic field, strain, and temperature, which opens up many applications ranging from magnetometry, temperature sensing to nanoscale NMR spectroscopy. In this talk we will discuss the application of diamond NV centers in nanoscale mechanical sensing at ambient conditions. |
Wednesday, March 6, 2019 5:18PM - 5:30PM |
P28.00015: Nanoscale mechanical sensing in aqueous solutions Kangwei Xia, Chufeng Liu, Weng Hang Leong, Man-Hin Kwok, Ren-Bao Liu, Quan Li
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