Coming off drugs: A critical history of the withdrawing body

Heroin withdrawal is perhaps one of the most taken-for-granted components of the addiction framework. Heroin users as well as researchers, policy makers, and practitioners have become dependent on it for thinking about and acting upon the process of heroin leaving the body. It is thought to be among the most challenging aspects of the recovery journey and has been linked to a range of public health, legal, and social problems. The taken-for-granted nature of heroin withdrawal has arguably limited its scrutiny in sociological and historical analyses. This article offers an alternative and critical perspective that draws attention to the heterogeneity of historical events and strategies that have left their mark on the withdrawing body of the heroin user. It maps changes in the discourse from the 18th century to the present and closes with developments in the neuroscience of addiction, which have relocated withdrawal from the body to the neurocircuitry of the brain and reframed it as a negative emotional state. This new language suggests the future of the discourse of withdrawal might be relatively short. The analysis moves beyond existing understandings of withdrawal as the simple absence of drugs from the body

Direct, Loss-Tolerant Characterization of Nonclassical Photon Statistics

We experimentally investigate a method of directly characterizing the photon number distribution of nonclassical light beams that is tolerant to losses and makes use only of standard binary detectors. This is achieved in a single measurement by calibrating the detector using some small amount of prior information about the source. We demonstrate the technique on a freely propagating heralded two-photon number state created by conditional detection of a two-mode squeezed state generated by a parametric downconverter.Comment: 5 pages, 2 figure

Precision metrology using weak measurements

Weak values and measurements have been proposed as means to achieve dramatic enhancements in metrology based on the greatly increased range of possible measurement outcomes. Unfortunately, the very large values of measurement outcomes occur with highly suppressed probabilities. This raises three vital questions in weak-measurement-based metrology, namely, (Q1) Does post-selection enhance the measurement precision? (Q2) Does weak measurement offer better precision than strong measurement? (Q3) Is it possible to beat the standard quantum limit or to achieve the Heisenberg limit with weak measurement using only classical resources? We analyse these questions for two prototypical, and generic, measurement protocols and show that while the answers to the first two questions are negative for both protocols, the answer to the last is affirmative for measurements with phase-space interactions, and negative for configuration space interactions. Our results, particularly the ability of weak measurements to perform at par with strong measurements in some cases, are instructive for the design of weak-measurement-based protocols for quantum metrology.Comment: 5+5 pages, 2 figure

Quantum Enhanced Multiple Phase Estimation

We study the simultaneous estimation of multiple phases as a discretised model for the imaging of a phase object. We identify quantum probe states that provide an enhancement compared to the best quantum scheme for the estimation of each individual phase separately, as well as improvements over classical strategies. Our strategy provides an advantage in the variance of the estimation over individual quantum estimation schemes that scales as O(d) where d is the number of phases. Finally, we study the attainability of this limit using realistic probes and photon-number-resolving detectors. This is a problem in which an intrinsic advantage is derived from the estimation of multiple parameters simultaneously.Comment: Accepted by Physical Review Letter