Quantum critical dynamics in a 5000-qubit programmable spin glass

Experiments on disordered alloys suggest that spin glasses can be brought into low-energy states faster by annealing quantum fluctuations than by conventional thermal annealing. Due to the importance of spin glasses as a paradigmatic computational testbed, reproducing this phenomenon in a programmable system has remained a central challenge in quantum optimization. Here we achieve this goal by realizing quantum critical spin-glass dynamics on thousands of qubits with a superconducting quantum annealer. We first demonstrate quantitative agreement between quantum annealing and time-evolution of the Schr\"odinger equation in small spin glasses. We then measure dynamics in 3D spin glasses on thousands of qubits, where simulation of many-body quantum dynamics is intractable. We extract critical exponents that clearly distinguish quantum annealing from the slower stochastic dynamics of analogous Monte Carlo algorithms, providing both theoretical and experimental support for a scaling advantage in reducing energy as a function of annealing time

Rationale and design of the Exercise Intensity Trial (EXCITE): A randomized trial comparing the effects of moderate versus moderate to high-intensity aerobic training in women with operable breast cancer

<p>Abstract</p> <p>Background</p> <p>The Exercise Intensity Trial (EXcITe) is a randomized trial to compare the efficacy of supervised moderate-intensity aerobic training to moderate to high-intensity aerobic training, relative to attention control, on aerobic capacity, physiologic mechanisms, patient-reported outcomes, and biomarkers in women with operable breast cancer following the completion of definitive adjuvant therapy.</p> <p>Methods/Design</p> <p>Using a single-center, randomized design, 174 postmenopausal women (58 patients/study arm) with histologically confirmed, operable breast cancer presenting to Duke University Medical Center (DUMC) will be enrolled in this trial following completion of primary therapy (including surgery, radiation therapy, and chemotherapy). After baseline assessments, eligible participants will be randomized to one of two supervised aerobic training interventions (moderate-intensity or moderate/high-intensity aerobic training) or an attention-control group (progressive stretching). The aerobic training interventions will include 150 mins.wk^-1of supervised treadmill walking per week at an intensity of 60%-70% (moderate-intensity) or 60% to 100% (moderate to high-intensity) of the individually determined peak oxygen consumption (VO_2peak) between 20-45 minutes/session for 16 weeks. The progressive stretching program will be consistent with the exercise interventions in terms of program length (16 weeks), social interaction (participants will receive one-on-one instruction), and duration (20-45 mins/session). The primary study endpoint is VO_2peak, as measured by an incremental cardiopulmonary exercise test. Secondary endpoints include physiologic determinants that govern VO_2peak, patient-reported outcomes, and biomarkers associated with breast cancer recurrence/mortality. All endpoints will be assessed at baseline and after the intervention (16 weeks).</p> <p>Discussion</p> <p>EXCITE is designed to investigate the intensity of aerobic training required to induce optimal improvements in VO_2peakand other pertinent outcomes in women who have completed definitive adjuvant therapy for operable breast cancer. Overall, this trial will inform and refine exercise guidelines to optimize recovery in breast and other cancer survivors following the completion of primary cytotoxic therapy.</p> <p>Trial Registration</p> <p>NCT01186367</p

Doctor of Philosophy

dissertationThis dissertation investigates the causes and consequences of effective monitoring by corporate boards of directors. I demonstrate that distortions to a board's ability and disposition to monitor management, represented by Board Co-option, affect the firm's credit quality. Firms with higher levels of Board Co-option receive lower credit ratings and larger credit spreads, especially when they are highly levered. I identify these effects through ordinary least squares estimations with fixed effects and through instrumental variables estimations, using director deaths as exogenous shocks to Board Co-option. I disentangle the effects of co-option from those of director-CEO connections and find that pre-appointment connections do not drive the adverse effects on credit quality. Instead, reductions in monitoring effectiveness appear to come from management capturing directors and earning their allegiance through the director's appointment to the board

Employee responses to CEO activism

We examine employee responses to CEO activism, the increasingly common practice of CEOs taking public stances on socio-political issues. CEO activism may bolster employees' identification with their organizations and strengthen shared beliefs among employees. Alternatively, CEO activism may alienate employees if CEO stances contrast with employees' ideologies. We find that employee satisfaction is higher when CEOs engage in activism that is aligned with employees’ ideologies. Furthermore, firms with CEO activism experience a net inflow of productive, ideologically-aligned inventors, which contributes to increased firm-level innovation. The improvements in employee satisfaction and innovation constitute an important channel that connects aligned CEO activism to increased firm value.24 month embargo; first published 10 May 2024This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Clawback Provisions and Firm Risk

Many of the events that trigger clawback provisions are associated with risky corporate policies and variable performance outcomes. We propose and test the hypothesis that clawback provisions motivate managers to reduce firm risk. Panel ordinary least squares, general method of moments with instrumental variables, and propensity square matching models all indicate that clawback provisions decrease the volatility of stock returns. The channels that connect clawback presence to firm risk include more conservative investment and financial policies. The clawback-induced reduction in risk-taking appears to benefit shareholders on average. The gains from reduced risk-taking are larger for firms with fewer growth options, lower R&D, and prior wrongdoing.24 month embargo; first published 31 January 2023This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]