A single photoelectron transistor for quantum optical communications

A single photoelectron can be trapped and its photoelectric charge detected by a source/drain channel in a transistor. Such a transistor photodetector can be useful for flagging the safe arrival of a photon in a quantum repeater. The electron trap can be photo-ionized and repeatedly reset for the arrival of successive individual photons. This single photoelectron transistor (SPT) operating at the lambda = 1.3 mu m tele-communication band, was demonstrated by using a windowed-gate double-quantum-well InGaAs/InAlAs/InP heterostructure that was designed to provide near-zero electron g-factor. The g-factor engineering allows selection rules that would convert a photon's polarization to an electron spin polarization. The safe arrival of the photo-electric charge would trigger the commencement of the teleportation algorithm

Direct Measurement of the Out-of-Plane Spin Texture in the Dirac Cone Surface State of a Topological Insulator

We have performed spin- and angle-resolved photoemission spectroscopy of Bi2Te3 and present the first direct evidence for the existence of the out-of-plane spin component on the surface state of a topological insulator. We found that the magnitude of the out-of-plane spin polarization on a hexagonally deformed Fermi surface (FS) of Bi2Te3 reaches maximally 25% of the in-plane counterpart while such a sizable out-of-plane spin component does not exist in the more circular FS of TlBiSe2, indicating that the hexagonal deformation of the FS is responsible for the deviation from the ideal helical spin texture. The observed out-of-plane polarization is much smaller than that expected from existing theory, suggesting that an additional ingredient is necessary for correctly understanding the surface spin polarization in Bi2Te3.Comment: 4 pages, 3 figure

A simple model of reactor cores for reactor neutrino flux calculations for the KamLAND experiment

KamLAND is a reactor neutrino oscillation experiment with a very long baseline. This experiment successfully measured oscillation phenomena of reactor antineutrinos coming mainly from 53 reactors in Japan. In order to extract the results, it is necessary to accurately calculate time-dependent antineutrino spectra from all the reactors. A simple model of reactor cores and code implementing it were developed for this purpose. This paper describes the model of the reactor cores used in the KamLAND reactor analysis.Comment: 14 pages, 7 figures, submitted to Nuclear Instruments and Methods in Physics Research

Immittance Matching for Multi-dimensional Open-system Photonic Crystals

An electromagnetic (EM) Bloch wave propagating in a photonic crystal (PC) is characterized by the immittance (impedance and admittance) of the wave. The immittance is used to investigate transmission and reflection at a surface or an interface of the PC. In particular, the general properties of immittance are useful for clarifying the wave propagation characteristics. We give a general proof that the immittance of EM Bloch waves on a plane in infinite one- and two-dimensional (2D) PCs is real when the plane is a reflection plane of the PC and the Bloch wavevector is perpendicular to the plane. We also show that the pure-real feature of immittance on a reflection plane for an infinite three-dimensional PC is good approximation based on the numerical calculations. The analytical proof indicates that the method used for immittance matching is extremely simplified since only the real part of the immittance function is needed for analysis without numerical verification. As an application of the proof, we describe a method based on immittance matching for qualitatively evaluating the reflection at the surface of a semi-infinite 2D PC, at the interface between a semi-infinite slab waveguide (WG) and a semi-infinite 2D PC line-defect WG, and at the interface between a semi-infinite channel WG and a semi-infinite 2D PC slab line-defect WG.Comment: 8 pages, 6 figure

Quantum key distribution over 30km of standard fiber using energy-time entangled photon pairs: a comparison of two chromatic dispersion reduction methods

We present a full implementation of a quantum key distribution system using energy-time entangled photon pairs and functioning with a 30km standard telecom fiber quantum channel. Two bases of two orthogonal states are implemented and the setup is quite robust to environmental constraints such as temperature variation. Two different ways to manage chromatic dispersion in the quantum channel are discussed.Comment: 10 pages, 4 figure

Equatorial and related non-equilibrium states in magnetization dynamics of ferromagnets: Generalization of Suhl's spin-wave instabilities

We investigate the nonlinear dynamics underlying the evolution of a 2-D nanoscale ferromagnetic film with uniaxial anisotropy in the presence of perpendicular pumping. Considering the associated Landau-Lifshitz spin evolution equation with Gilbert damping together with Maxwell equation for the demagnetization field, we study the dynamics in terms of the stereographic variable. We identify several new fixed points for suitable choice of external field in a rotating frame of reference. In particular, we identify explicit equatorial and related fixed points of the spin vector in the plane transverse to the anisotropy axis when the pumping frequency coincides with the amplitude of the static parallel field. We then study the linear stability of these novel fixed points under homogeneous and spin wave perturbations and obtain a generalized Suhl's instability criterion, giving the condition for exponential growth of P-modes under spin wave perturbations. Two parameter phase diagrams (in terms of amplitudes of static parallel and oscillatory perpendicular magnetic fields) for stability are obtained, which differ qualitatively from those for the conventional ferromagnetic resonance near thermal equilibrium and are amenable to experimental tests.Comment: 23 pages, 5 figures, To appear in Physica

21-An Intensive Archaeological Survey of the James and Ellen G. White House Site (20CA118), Battle Creek, Michigan

An intensive archaeological survey was conducted at the James and Ellen G. White House site (20CA118) in Battle Creek, Michigan over a seven-week period from May 4-June 24, 1998. The house is a well-known local landmark that was occupied from 1856-1863 by a family that was instrumental in founding the Seventh-day Adventist denominational movement. Although the original site has been subdivided and subjected to significant modification since the third quarter of the 19th century, the 1856 wood-frame Greek Revival house remains extant. Investigations were oriented towards identifying the presence of subsurface archaeological remains and site features that can inform about the landscapes and social identities of the 19th century occupants and subsequent changes. Documentary evidence suggested the presence of various outbuildings and other landscape features that were typically associated with mid-19th century suburban households in the region. The purpose of the survey was to identify and evaluate material traces of buildings and activity areas in the vicinity of the house and the adjacent property to the south. The identification of archaeologically-sensitive areas would assist preservation planning by the Historic Adventist Village in their efforts to develop the neighborhood for interpretive and religious purposes. A geophysical survey employing magnetometry, soil conductivity, and ground penetrating radar was conducted to locate subsurface anomalies of potential archaeological interest. These results-along with information from local informants, surficial clues, and limited testing in 1996-were used to guide the placement of 29 hand-excavated units of varying size. Our survey indicates that the site of lot 64 in Manchester\u27s 3rd Addition has experienced disturbances, particularly in the areas south and west of the White\u27s house. However, investigations also exposed artifacts and features in undisturbed contexts from the mid-19th century through the present. Thus, there appear to be intact material deposits with contextual integrity, some of which probably date to the period associated with the Whites\u27 occupation of the house. Noteworthy artifacts and features include: significant quantities of mid-19th century ceramic types, canning jar fragments that may date to the third quarter of the 19th century (1858-1875), a cement-plastered cistern, and a possible root cellar in the door yard immediately behind the house. Given the presence of these deposits, the site appears eligible for inclusion in the National Register of Historical Places. Furthermore, we recommend that subsurface disturbance be avoided in these areas of the site until further evaluation can be conducted