Jeffrey H. Shapiro

Bio: Jeffrey H. Shapiro is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Photon & Quantum key distribution. The author has an hindex of 65, co-authored 395 publications receiving 17401 citations.

Large-alphabet encoding schemes for floodlight quantum key distribution

Abstract: Floodlight quantum key distribution (FL-QKD) uses binary phase-shift keying (BPSK) of multiple optical modes to achieve Gbps secret-key rates (SKRs) at metropolitan-area distances. We show that FL-QKD's SKR can be doubled by using 32-ary PSK.

Self-Focusing Limitations on Squeezed State Generation in Two-Level Media

Abstract: Despite theoretical predictions1,2—which indicate that substantial squeezing should be achievable using four-wave mixing in two-level media—sodium-beam and sodium-vapor experiments have delivered inferred squeezing of at most 60%.3,4 In this paper we report results of a series of sodium-vapor squeezing experiments undertaken to confirm the validity of our quantum theory of nondegenerate multiwave mixing.2,5 During the course of these measurements, we have identified the likely cause for the foregoing discrepancy between theory and experiment—the differential pump-probe self-focusing (DPS) effect. The DPS effect refers to the different amount of self-focusing/defocusing experienced by the intense pump and the weak probe Gaussian beams of the four-wave mixer. In essence, it is the transverse beam-pattern version of the nonlinear pump-probe phase mismatch encountered in fiber-optic and other colinear squeezed-state generators.6 DPS reduces the mode-matching efficiency inside the four-wave mixer’s interaction region and thus imposes an upper limit on the effective interaction length.

Attacking quantum key distribution with single-photon two-qubit quantum logic

Abstract: The Fuchs-Peres-Brandt (FPB) probe realizes the most powerful individual attack on BB84 quantum key distribution. A physical simulation of the FPB-probe attack using single-photon two-qubit quantum logic is described.

LADAR resolution improvement using squeezed‐vacuum injection

Abstract: We evaluate the signal‐to‐noise ratio (SNR) dependence of LADAR spatial resolution, and the improvement afforded by squeezed‐vacuum injection at the receiver. We define spatial resolution as the ability to distinguish two point targets from a single point target. For speckle returns and a soft‐aperture homodyne receiver, the resolution scales as SNR−3/10 at high SNR, and exhibits a threshold SNR below which targets are unresolvable. Injecting a 15 dB squeezed vacuum improves the resolution by a factor of about 2 at high SNR, and provides approximately 3.5 dB of threshold extension, which permits some classically‐unresolvable targets to become distinguishable.

High-flux entanglement sources using periodically-poled nonlinear crystals

Abstract: We have efficiently generated colinearly-propagrating entangled photon pairs from nondegenerate type-I and degenerate type-II quasi-phase matched parametric downconverters based on periodically-poled lithium niobate and potassium titanyl phosphate, respectively.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

The Observation of Gravitational Waves from a Binary Black Hole Merger

Abstract: On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160) Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

Computer vision : a modern approach = 计算机视觉 : 一种现代的方法

Abstract: From the Publisher: The accessible presentation of this book gives both a general view of the entire computer vision enterprise and also offers sufficient detail to be able to build useful applications. Users learn techniques that have proven to be useful by first-hand experience and a wide range of mathematical methods. A CD-ROM with every copy of the text contains source code for programming practice, color images, and illustrative movies. Comprehensive and up-to-date, this book includes essential topics that either reflect practical significance or are of theoretical importance. Topics are discussed in substantial and increasing depth. Application surveys describe numerous important application areas such as image based rendering and digital libraries. Many important algorithms broken down and illustrated in pseudo code. Appropriate for use by engineers as a comprehensive reference to the computer vision enterprise.

Terabit free-space data transmission employing orbital angular momentum multiplexing

Abstract: Researchers demonstrate the ability to multiplex and transfer data between twisted beams of light with different amounts of orbital angular momentum — a development that provides new opportunities for increasing the data capacity of free-space optical communications links.