Digital Switching in the Quantum Domain

In this paper, we present an architecture and implementation algorithm such that digital data can be switched in the quantum domain. First we define the connection digraph which can be used to describe the behavior of a switch at a given time, then we show how a connection digraph can be implemented using elementary quantum gates. The proposed mechanism supports unicasting as well as multicasting, and is strict-sense non-blocking. It can be applied to perform either circuit switching or packet switching. Compared with a traditional space or time domain switch, the proposed switching mechanism is more scalable. Assuming an n-by-n quantum switch, the space consumption grows linearly, i.e. O(n), while the time complexity is O(1) for unicasting, and O(log n) for multicasting. Based on these advantages, a high throughput switching device can be built simply by increasing the number of I/O ports.Comment: 24 pages, 16 figures, LaTe

Microfluidic immunomagnetic multi-target sorting – a model for controlling deflection of paramagnetic beads

We describe a microfluidic system that uses a magnetic field to sort paramagnetic beads by deflecting them in the direction normal to the flow. Our experiments systematically study the dependence of the beads’ deflection on: bead size and susceptibility, magnet strength, fluid speed and viscosity, and device geometry. We also develop a design parameter that can aid in the design of microfluidic devices for immunomagnetic multi-target sorting

EffiTest: Efficient Delay Test and Statistical Prediction for Configuring Post-silicon Tunable Buffers

At nanometer manufacturing technology nodes, process variations significantly affect circuit performance. To combat them, post- silicon clock tuning buffers can be deployed to balance timing bud- gets of critical paths for each individual chip after manufacturing. The challenge of this method is that path delays should be mea- sured for each chip to configure the tuning buffers properly. Current methods for this delay measurement rely on path-wise frequency stepping. This strategy, however, requires too much time from ex- pensive testers. In this paper, we propose an efficient delay test framework (EffiTest) to solve the post-silicon testing problem by aligning path delays using the already-existing tuning buffers in the circuit. In addition, we only test representative paths and the delays of other paths are estimated by statistical delay prediction. Exper- imental results demonstrate that the proposed method can reduce the number of frequency stepping iterations by more than 94% with only a slight yield loss.Comment: ACM/IEEE Design Automation Conference (DAC), June 201

Optical probes of the quantum vacuum: The photon polarization tensor in external fields

The photon polarization tensor is the central building block of an effective theory description of photon propagation in the quantum vacuum. It accounts for the vacuum fluctuations of the underlying theory, and in the presence of external electromagnetic fields, gives rise to such striking phenomena as vacuum birefringence and dichroism. Standard approximations of the polarization tensor are often restricted to on-the-light-cone dynamics in homogeneous electromagnetic fields, and are limited to certain momentum regimes only. We devise two different strategies to go beyond these limitations: First, we aim at obtaining novel analytical insights into the photon polarization tensor for homogeneous fields, while retaining its full momentum dependence. Second, we employ wordline numerical methods to surpass the constant-field limit.Comment: 13 pages, 4 figures; typo in Eq. (5) corrected (matches journal version

Association between religious service attendance and lower suicide rates among US women

IMPORTANCE: Previous studies have linked suicide risk with religious participation, but the majority have used ecologic, cross-sectional, or case-control data. OBJECTIVE: To examine the longitudinal association between religious service at tendance and suicide and the joint associations of suicide with service attendance and religious affiliation. DESIGN, SETTING, AND PARTICIPANTS: We evaluated associations between religious service attendance and suicide from 1996 through June 2010 in a large, long-term prospective cohort, the Nurses' Health Study, in an analysis that included 89 708 women. Religious service attendance was self-reported in 1992 and 1996. Data analysis was conducted from 1996 through 2010. MAIN OUTCOMES AND MEASURES: Cox proportional hazards regression models were used to examine the association between religious service attendance and suicide, adjusting for demographic covariates, lifestyle factors, medical history, depressive symptoms, and social integration measures. We performed sensitivity analyses to examine the influence of unmeasured confounding. RESULTS: Among 89 708 women aged 30 to 55 years who participated in the Nurses' Health Study, attendance at religious services once per week or more was associated with an approximately 5-fold lower rate of suicide compared with never attending religious services (hazard ratio, 0.16; 95% CI, 0.06-0.46). Service attendance once or more per week vs less frequent attendance was associated with a hazard ratio of 0.05 (95% CI, 0.006-0.48) for Catholics but only 0.34 (95% CI, 0.10-1.10) for Protestants (P = .05 for heterogeneity). Results were robust in sensitivity analysis and to exclusions of persons who were previously depressed or had a history of cancer or cardiovascular disease. There was evidence that social integration, depressive symptoms, and alcohol consumption partially mediated the association among those occasionally attending services, but not for those attending frequently. CONCLUSIONS AND RELEVANCE: In this cohort of US women, frequent religious service attendance was associated with a significantly lower rate of suicide

Metamaterials: optical activity without chirality

We report that the classical phenomenon of optical activity, which is traditionally associated with chirality (helicity) of organic molecules, proteins, and inorganic structures, can be observed in artificial planar media which exhibit neither 3D nor 2D chirality. We observe the effect in the microwave and optical parts of the spectrum at oblique incidence to regular arrays of nonchiral subwavelength metamolecules in the form of strong circular dichroism and birefringence indistinguishable from those of chiral three-dimensional media