Entanglement dynamics of two qubits under the influence of external kicks and Gaussian pulses

We have investigated the dynamics of entanglement between two spin-1/2 qubits that are subject to independent kick and Gaussian pulse type external magnetic fields analytically as well as numerically. Dyson time ordering effect on the dynamics is found to be important for the sequence of kicks. We show that "almost-steady" high entanglement can be created between two initially unentangled qubits by using carefully designed kick or pulse sequences

Complete population transfer in a degenerate 3-level atom

We find conditions required to achieve complete population transfer, via coherent population trapping, from an initial state to a designated final state at a designated time in a degenerate 3-level atom, where transitions are caused by an external interaction. Complete population transfer from an initially occupied state 1 to a designated state 2 occurs under two conditions. First, there is a constraint on the ratios of the transition matrix elements of the external interaction. Second, there is a constraint on the action integral over the interaction, or "area", corresponding to the phase shift induced by the external interaction. Both conditions may be expressed in terms of simple odd integers.Comment: 22 pages, 4 figure

Histopathologically Proven Autoimmune Pancreatitis Mimicking Neuroendocrine Tumor or Pancreatic Cancer

Autoimmune pancreatitis (AIP) can be difficult to distinguish from pancreatic cancer. We report a case of histopathologically proven AIP mimicking neuroendocrine tumor (NET) or pancreatic cancer in a 53-year-old man. He was referred to our hospital for further evaluation of a pancreatic mass detected on ultrasonography at a medical check-up. Abdominal ultrasonography showed a 15-mm hypoechoic mass located in the pancreatic body. Computed tomography revealed a tumor without any contrast enhancement, and magnetic resonance imaging demonstrated the mass to be hyperintense on diffusion-weighted image. Endoscopic retrograde cholangiopancreatography revealed slight dilatation of a branch of the pancreatic duct without stricture of the main pancreatic duct. The common bile duct seemed intact. Under suspicion of a non-functioning NET or malignant neoplasm, laparotomy was performed. At laparotomy, an elastic firm and well-circumscribed mass was found suggestive of a non-functioning NET, thus enucleation was performed. Histopathologically, the lesion corresponded to AIP

Monitoring of the operating parameters of the KATRIN Windowless Gaseous Tritium Source

The KArlsruhe TRItium Neutrino (KATRIN) experiment will measure the absolute mass scale of neutrinos with a sensitivity of mnu = 200 meV/c2 by high-precision spectroscopy close to the tritium beta-decay endpoint at 18.6 keV. Its Windowless Gaseous Tritium Source (WGTS) is a beta-decay source of high intensity (1011 s−1) and stability, where high-purity molecular tritium at 30 K is circulated in a closed loop with a yearly throughput of 10 kg. To limit systematic effects the column density of the source has to be stabilized at the 10−3 level. This requires extensive sensor instrumentation and dedicated control and monitoring systems for parameters such as the beam tube temperature, injection pressure, gas composition and so on. In this paper, we give an overview of these systems including a dedicated laser-Raman system as well as several beta-decay activity monitors. We also report on the results of the WGTS demonstrator and other large-scale test experiments giving proof-of-principle that all parameters relevant to the systematics can be controlled and monitored on the 10−3 level or better. As a result of these works, the WGTS systematics can be controlled within stringent margins, enabling the KATRIN experiment to explore the neutrino mass scale with the design sensitivity