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Minimum error-probability laser radar point-target localization is analyzed, including the effects of dark counts, background counts, and target speckle. Results from preliminary table-top experiments are reported.

This report summarizes our accomplishments in the past 3+1 years concerning our investigation into the advantages of weak value approaches to precision measurements, as well as other investigations into weak measurements and weak values. The report is divided into two sections: The first focuses on a detailed discussion of results concerning applications and advantages of weak value amplification techniques to precision measurement. Here, we discuss four separate but connected projects. The first concerns the possibility of reusing the rejected photons in the post-selection portion of the weak value amplification. The second project concerns the technical merits of weak value amplification. We also discuss a third project using our interferometric weak value technique to make precision frequency measurements on an optical beam, reporting a resolution of 129 +/- 7 kHz per root Hz with only 2 mW of continuous-wave power. The fourth project deals with a weak value inspired phase amplification technique. The second main part of the report concerns results related to weak measurements and weak values, but not directly related to the amplification issue. We give a brief survey of our results in this area. We have investigated weak measurements as a test of quantum mechanics, by deriving generalized Leggett-Garg inequalities for multiple parties and violating them with entangled photons. We have extensively investigated a new approach to generalized measurement we call contextual values, which gives a precise connection between an indirectly measured system and the outcomes of the detector by assigning a set of generalized eigenvalues to each detector outcome. This assignment permits a principled definition of a conditioned average, which limits to the weak value under certain conditions that are usually satisfied in the laboratory. We have also discussed the significance of the imaginary part of the weak value., The original document contains color images.

We present a measurement protocol for discriminating between two different quantum states of a qubit with high fidelity. The protocol, called null value, is comprised of a projective measurement performed on the system with a small probability (also known as partial collapse), followed by a tuned postselection. We report on an optical experimental implementation of the scheme. We show that our protocol leads to an amplified signal-to-noise ratio (as compared with a straightforward strong measurement) when discerning between the two quantum states.

In this Letter, we derive an entropic Einstein-Podolsky-Rosen (EPR) steering inequality for continuous-variable systems using only experimentally measured discrete probability distributions and details of the measurement apparatus. We use this inequality to witness EPR steering between the positions and momenta of photon pairs generated in spontaneous parametric down-conversion. We examine the asymmetry between parties in this inequality, and show that this asymmetry can be used to reduce the technical requirements of experimental setups intended to demonstrate the EPR paradox. Furthermore, we develop a more stringent steering inequality that is symmetric between parties, and use it to show that the down-converted photon pairs also exhibit symmetric EPR steering.

High-dimensional Hilbert spaces used for quantum communication channels offer the possibility of large data transmission capabilities. We propose a method of characterizing the channel capacity of an entangled photonic state in high-dimensional position and momentum bases. We use this method to measure the channel capacity of a parametric down-conversion state by measuring in up to 576 dimensions per detector. We achieve a channel capacity over 7 bits/photon in either the position or momentum basis. Furthermore, we provide a correspondingly high-dimensional separability bound that suggests that the channel performance cannot be replicated classically., United States. Defense Advanced Research Projects Agency. System Science Division. Defense Sciences Office (Grant No. W911NF- 10-1-0404), United States. Army Research Office. Multidisciplinary University Research Initiative (Grant No. W911NF-05-1- 0197)

Atmospheric turbulence generally affects the resolution and visibility of an image in long-distance imaging. In a recent quantum ghost imaging experiment [P. B. Dixon et al. Phys. Rev. A 83 051803 (2011)], it was found that the effect of the turbulence can nevertheless be mitigated under certain conditions. This paper gives a detailed theoretical analysis to the setup and results reported in the experiment. Entangled photons with a finite correlation area and a turbulence model beyond the phase screen approximation are considered., United States. Defense Advanced Research Projects Agency. System Science Division. Defense Sciences Office (InPho Grant No. W911NF-10-1-0404), United States. Army Research Office. Multidisciplinary University Research Initiative (Grant No. W911NF-05-1-0197)

We investigate the effect of turbulence on quantum ghost imaging. We use entangled photons and demonstrate that for a specific experimental configuration the effect of turbulence can be greatly diminished. By decoupling the entangled photon source from the ghost-imaging central image plane, we are able to dramatically increase the ghost-image quality. When imaging a test pattern through turbulence, this method increases the imaged pattern visibility from V=0.15±0.04 to 0.42±0.04., United States. Defense Advanced Research Projects Agency (DARPA DSO InPho Grant No. W911NF-10-1-0404), United States. Army Research Office (USARO MURI Grant No. W911NF-05-1-0197)