Probing a spin transfer controlled magnetic nanowire with a single nitrogen-vacancy spin in bulk diamond

The point-like nature and exquisite magnetic field sensitivity of the nitrogen vacancy (NV) center in diamond can provide information about the inner workings of magnetic nanocircuits in complement with traditional transport techniques. Here we use a single NV in bulk diamond to probe the stray field of a ferromagnetic nanowire controlled by spin transfer (ST) torques. We first report an unambiguous measurement of ST tuned, parametrically driven, large-amplitude magnetic oscillations. At the same time, we demonstrate that such magnetic oscillations alone can directly drive NV spin transitions, providing a potential new means of control. Finally, we use the NV as a local noise thermometer, observing strong ST damping of the stray field noise, consistent with magnetic cooling from room temperature to $\sim$150 K.Comment: 6 pages, 5 figures, plus supplementary informatio

Higher-Order Methods for Hamiltonian Engineering Pulse Sequence Design

We introduce a framework for designing Hamiltonian engineering pulse sequences that systematically accounts for the effects of higher-order contributions to the Floquet-Magnus expansion. Our techniques result in simple, intuitive decoupling rules, despite the higher-order contributions naively involving complicated, non-local-in-time commutators. We illustrate how these rules can be used to efficiently design improved Hamiltonian engineering pulse sequences for a wide variety of tasks, such as dynamical decoupling, quantum sensing, and quantum simulation.Comment: 12+10 pages, 6 figures, see accompanying paper "Robust Higher-Order Hamiltonian Engineering for Quantum Sensing with Strongly Interacting Systems" for application of these techniques to quantum sensin

Robust Higher-Order Hamiltonian Engineering for Quantum Sensing with Strongly Interacting Systems

Dynamical decoupling techniques constitute an integral part of many quantum sensing platforms, often leading to orders-of-magnitude improvements in coherence time and sensitivity. Most AC sensing sequences involve a periodic echo-like structure, in which the target signal is synchronized with the echo period. We show that for strongly interacting systems, this construction leads to a fundamental sensitivity limit associated with imperfect interaction decoupling. We present a simple physical picture demonstrating the origin of this limitation, and further formalize these considerations in terms of concise higher-order decoupling rules. We then show how these limitations can be surpassed by identifying a novel sequence building block, in which the signal period matches twice the echo period. Using these decoupling rules and the resulting sequence building block, we experimentally demonstrate significant improvements in dynamical decoupling timescales and magnetic field sensitivity, opening the door for new applications in quantum sensing and quantum many-body physics.Comment: 5 pages, 3 figures, see accompanying paper "Higher-Order Methods for Hamiltonian Engineering Pulse Sequence Design" for details on Hamiltonian engineering technique

Controlling local thermalization dynamics in a Floquet-engineered dipolar ensemble

Understanding the microscopic mechanisms of thermalization in closed quantum systems is among the key challenges in modern quantum many-body physics. We demonstrate a method to probe local thermalization in a large-scale many-body system by exploiting its inherent disorder, and use this to uncover the thermalization mechanisms in a three-dimensional, dipolar-interacting spin system with tunable interactions. Utilizing advanced Hamiltonian engineering techniques to explore a range of spin Hamiltonians, we observe a striking change in the characteristic shape and timescale of local correlation decay as we vary the engineered exchange anisotropy. We show that these observations originate from the system's intrinsic many-body dynamics and reveal the signatures of conservation laws within localized clusters of spins, which do not readily manifest using global probes. Our method provides an exquisite lens into the tunable nature of local thermalization dynamics, and enables detailed studies of scrambling, thermalization and hydrodynamics in strongly-interacting quantum systems.Comment: 6 pages, 4 figures main tex

Robust Hamiltonian Engineering for Interacting Qudit Systems

We develop a formalism for the robust dynamical decoupling and Hamiltonian engineering of strongly interacting qudit systems. Specifically, we present a geometric formalism that significantly simplifies qudit pulse sequence design, while incorporating the necessary robustness conditions. We experimentally demonstrate these techniques in a strongly-interacting, disordered ensemble of spin-1 nitrogen-vacancy centers, achieving over an order of magnitude improvement in coherence time over existing pulse sequences. We further describe how our techniques enable the engineering of exotic many-body phenomena such as quantum many-body scars, and allow enhanced sensitivities for quantum metrology. These results enable the engineering of a whole new class of complex qudit Hamiltonians, with wide-reaching applications in dynamical decoupling, many-body physics and quantum metrology.Comment: 15+12 pages, 11+7 figures, comments welcome

Robust Hamiltonian Engineering for Interacting Qudit Systems

Dynamical decoupling and Hamiltonian engineering are well-established techniques that have been used to control qubit systems. However, designing the corresponding methods for qudit systems has been challenging due to the lack of a Bloch sphere representation, more complex interactions, and additional control constraints. By identifying several general structures associated with such problems, we develop a formalism for the robust dynamical decoupling and Hamiltonian engineering of strongly interacting qudit systems. Our formalism significantly simplifies qudit pulse-sequence design while naturally incorporating robustness conditions necessary for experimental practicality. We experimentally demonstrate these techniques in a strongly interacting, disordered ensemble of spin-1 nitrogen-vacancy centers, achieving more than an order-of-magnitude improvement in coherence time over existing pulse sequences. We further describe how our techniques enable the engineering of exotic many-body phenomena such as quantum many-body scars, and open up new opportunities for quantum metrology with enhanced sensitivities. These results enable wide-reaching new applications for dynamical decoupling and Hamiltonian engineering in many-body physics and quantum metrology

The MEMORY Study: MulticentEr study of Minimally invasive surgery versus Open Radical hYsterectomy in the management of early-stage cervical cancer: Survival outcomes.

OBJECTIVE: The Laparoscopic Approach to Cervical Cancer (LACC) trial found that minimally invasive radical hysterectomy compared to open radical hysterectomy compromised oncologic outcomes and was associated with worse progression-free survival (PFS) and overall survival (OS) in early-stage cervical carcinoma. We sought to assess oncologic outcomes at multiple centers between minimally invasive (MIS) radical hysterectomy and OPEN radical hysterectomy. METHODS: This is a multi-institutional, retrospective cohort study of patients with 2009 FIGO stage IA1 (with lymphovascular space invasion) to IB1 cervical carcinoma from 1/2007-12/2016. Patients who underwent preoperative therapy were excluded. Squamous cell carcinoma, adenocarcinoma, and adenosquamous carcinomas were included. Appropriate statistical tests were used. RESULTS: We identified 1093 cases for analysis-715 MIS (558 robotic [78%]) and 378. OPEN procedures. The OPEN cohort had more patients with tumors \u3e2 cm, residual disease in the hysterectomy specimen, and more likely to have had adjuvant therapy. Median follow-up for the MIS and OPEN cohorts were 38.5 months (range, 0.03-149.51) and 54.98 months (range, 0.03-145.20), respectively. Three-year PFS rates were 87.9% (95% CI: 84.9-90.4%) and 89% (95% CI: 84.9-92%), respectively (P = 0.6). On multivariate analysis, the adjusted HR for recurrence/death was 0.70 (95% CI: 0.47-1.03; P = 0.07). Three-year OS rates were 95.8% (95% CI: 93.6-97.2%) and 96.6% (95% CI: 93.8-98.2%), respectively (P = 0.8). On multivariate analysis, the adjusted HR for death was 0.81 (95% CI: 0.43-1.52; P = 0.5). CONCLUSION: This multi-institutional analysis showed that an MIS compared to OPEN radical hysterectomy for cervical cancer did not appear to compromise oncologic outcomes, with similar PFS and OS

Precision measurement of the structure of the CMS inner tracking system using nuclear interactions

The structure of the CMS inner tracking system has been studied using nuclear interactions of hadrons striking its material. Data from proton-proton collisions at a center-of-mass energy of 13 TeV recorded in 2015 at the LHC are used to reconstruct millions of secondary vertices from these nuclear interactions. Precise positions of the beam pipe and the inner tracking system elements, such as the pixel detector support tube, and barrel pixel detector inner shield and support rails, are determined using these vertices. These measurements are important for detector simulations, detector upgrades, and to identify any changes in the positions of inactive elements