Entropy Burst from Parabolic Potentials

The change of the energy of ground state is investigated in a thermodynamical process by using the model described by one-dimensional harmonic oscillator + two-dimensional isotropic parabolic potential barrier such as $V(x,y,z)=m\omega^2 x^2/2 -m\gamma^2 (y^2+z^2)/2$. In the process where two independent many-particle systems suddenly touch with each other, it is shown that the lowest energy after the interaction can possibly be smaller than that before the interaction and then the entropy burst can occur.Comment: 6 pages, AmS-LaTeX, 1 figur

Gain tuning and fidelity in continuous variable quantum teleportation

The fidelity of continuous variable teleportation can be optimized by changing the gain in the modulation of the output field. We discuss the gain dependence of fidelity for coherent, vacuum and one photon inputs and propose optimal gain tuning strategies for corresponding input selections.Comment: 23 pages, 10 figure

Information extraction and quantum state distortions in continuous variable quantum teleportation

We analyze the loss of fidelity in continuous variable teleportation due to non-maximal entanglement. It is shown that the quantum state distortions correspond to the measurement back-action of a field amplitude measurement. Results for coherent states and for photon number states are presented.Comment: 4 pages Latex, contribution to the proceedings of the ISQM'01 conference held August 27th to 30th in Toky

Fidelity and information in the quantum teleportation of continuous variables

Ideally, quantum teleportation should transfer a quantum state without distortion and without providing any information about that state. However, quantum teleportation of continuous electromagnetic field variables introduces additional noise, limiting the fidelity of the quantum state transfer. In this article, the operator describing the quantum state transfer is derived. The transfer operator modifies the probability amplitudes of the quantum state in a shifted photon number base by enhancing low photon numbers and suppressing high photon numbers. This modification of the statistical weight corresponds to a measurement of finite resolution performed on the original quantum state. The limited fidelity of quantum teleportation is thus shown to be a direct consequence of the information obtained in the measurement.Comment: 10 pages, including one figure, minor clarifications and added referenc

Transabdominal Preperitoneal Repair for Obturator Hernia

信州大学博士（医学）・学位論文・平成23年3月31日授与（甲第889号）・横山隆秀Background A laparoscopic surgical approach for obturator hernia (OH) repair is uncommon. The aim of the present study was to assess the effectiveness of laparoscopic transabdominal preperitoneal (TAPP) repair for OH. Methods From 2001 to May 2010, 659 patients with inguinal hernia underwent TAPP repair at in our institutes. Among these, the eight patients with OH were the subjects of this study. Results Three of the eight patients were diagnosed as having occult OH, and the other five were diagnosed preoperatively, by ultrasonography and/or computed tomography, as having strangulated OH. Bilateral OH was found in five patients (63%), and combined groin hernias, either unilaterally or bilaterally, were observed in seven patients (88%), all of whom had femoral hernia. Of the five patients with bowel obstruction at presentation, four were determined not to require resection after assessment of the intestinal viability by laparoscopy. There was one case of conversion to a two-stage hernia repair performed to avoid mesh contamination: addition of mini-laparotomy, followed by extraction of the gangrenous intestine for resection and anastomosis with simple peritoneal closure of the hernia defect in the first stage, and a Kugel hernia repair in the second stage. There was no incidence of postoperative morbidity, mortality, or recurrence. Conclusions Because TAPP allows assessment of not only the entire groin area bilaterally but also simultaneous assessment of the viability of the incarcerated intestine with a minimum abdominal wall defect, we believe that it is an adequate approach to the treatment of both occult and acutely incarcerated OH. Two-stage hernia repair is technically feasible in patients requiring resection of the incarcerated intestine.ArticleWORLD JOURNAL OF SURGERY. 35(10):2323-2327 (2011)journal articl