Quantum computation features known examples of hardware acceleration for certain problems, but is challenging to realize because of its susceptibility to small errors from noise or imperfect control. The principles of fault tolerance may enable computational acceleration with imperfect hardware, but they place strict requirements on the character and correlation of errors. For many qubit technologies, some challenges to achieving fault tolerance can be traced to correlated errors arising from the need to control qubits by injecting microwave energy matching qubit resonances.
View Article and Find Full Text PDFIntroduction: Advances in specialized medical areas and updated clinical guidelines show a need for a focused approach for patients with specific disorders.
Objective: To describe a multidisciplinary tumor board for patients with endocrine tumors.
Methods: We established an endocrine tumor board at a large health maintenance organization and studied cases presented between September 2007 and August 2017.
Like modern microprocessors today, future processors of quantum information may be implemented using all-electrical control of silicon-based devices. A semiconductor spin qubit may be controlled without the use of magnetic fields by using three electrons in three tunnel-coupled quantum dots. Triple dots have previously been implemented in GaAs, but this material suffers from intrinsic nuclear magnetic noise.
View Article and Find Full Text PDFFirst bite syndrome is a well-described sequelae of parapharyngeal space surgery, thought to result from sympathetic denervation of the parotid gland. We describe a case of first bite syndrome caused by an adenoid cystic carcinoma of the submandibular gland. The tumor was not clinically or radiographically apparent until 18 months after initial presentation despite repeated imaging.
View Article and Find Full Text PDFRealizing the theoretical promise of quantum computers will require overcoming decoherence. Here we demonstrate numerically that high fidelity quantum gates are possible within a framework of quantum dynamical decoupling. Orders of magnitude improvement in the fidelities of a universal set of quantum gates, relative to unprotected evolution, is achieved over a broad range of system-environment coupling strengths, using recursively constructed (concatenated) dynamical decoupling pulse sequences.
View Article and Find Full Text PDFWe present a near-optimal quantum dynamical decoupling scheme that eliminates general decoherence of a qubit to order n using O(n2) pulses, an exponential decrease in pulses over all previous decoupling methods. Numerical simulations of a qubit coupled to a spin bath demonstrate the superior performance of the new pulse sequences.
View Article and Find Full Text PDFInt J Radiat Oncol Biol Phys
March 2004
Purpose: To determine the feasibility and toxicity of delivering stereotactic radiosurgery to patients with locally advanced pancreatic cancer.
Methods And Materials: Patients with Eastern Cooperative Oncology Group performance status < or=2 and locally advanced pancreatic cancer were enrolled on this Phase I dose escalation study. Patients received a single fraction of radiosurgery consisting of either 15 Gy, 20 Gy, or 25 Gy to the primary tumor.