Control with EIT: High energy charged particle detection

The strong non-linear optical response of atomic systems in electromagnetically induced transparency (EIT) states is considered as a means to detect the presence of small perturbations to steady states. For the 3-level system, expressions for the group velocity and group velocity dispersion (GVD) were derived and a quantum control protocol was established to account for the change in the chirp spectrum of a probe pulse when the steady state was perturbed. This was applied to the propagation of slow Cherenkov polaritons in the medium due to the passage of a train of high-energy charged particles (high energy particles). The choice of the initial steady state with focus on the slow light condition and strong narrowly confined dispersion, equated to the continuous trapping of Cherenkov polaritons in the medium along a narrow group cone, allowing for non-trivial fields to accumulate. Considering another medium prepared for the detection of the radiation, sweeping of the control field and detuning parameters in the field-atom parameter space showed the presence of optimal regions to maximize the first order perturbation in the coherences creating changes in the optical responses that modify the chirp spectra of probe pulses.Comment: 32 pages, 9 figure

Aryabhata and the Construction of the First Trigonometric Table

Few among us would know that the first mention of the sine and the enumeration of the first sine table are to be credited to Aryabhata. The method to generate this relies on the sine difference formula which is derived using ingenious arguments based on similar triangles. We describe how this was done. In order to make our presentation pedagogical we take a unit circle and radians instead of the (now) archaic notation in the Aryabhatiya and its commentators. We suggest a couple of exercise problems and invite the enterprising student to try their hands. We also point out that his sine and the second sine difference identities are related to the finite difference calculus we now routinely use to calculate derivatives and second derivatives. An understanding of these trigonometric identities and preparation of the sine table will enable a student to get an appreciation of the path breaking work of Aryabhata.Comment: 11 pages and 2 figures one of the figures is .png the other figure is embedded as tik

Electroweak Sudakov Corrections using Effective Field Theory

Electroweak Sudakov corrections of the form alpha^n log^m s/M_{W,Z}^2 are summed using renormalization group evolution in soft-collinear effective theory (SCET). Results are given for the scalar, vector and tensor form-factors for fermion and scalar particles. The formalism for including massive gauge bosons in SCET is developed.Comment: 5 page

Sleep Timing and Neurocognitive Networks in Youth

Sleep timing, particularly later midpoint of sleep, has been linked to emotion dysregulation and psychopathology. Prior adult studies link poor sleep (e.g., shorter duration, later midpoint), to altered resting-state functional connectivity (rs-FC) within and between key neurocognitive networks, particularly the default mode network (DMN), which is involved in internal thought and rumination. Importantly, many psychiatric disorders begin during adolescence, a period of shifted sleep schedules. We explored associations between midpoint of sleep and rs-FC of the DMN and other core neurocognitive networks in youth. Sleep timing was measured in 3,798 youth (11.9±0.6 years, 47.5% female) from the Adolescent Brain Cognitive Development study using Fitbit watches (over 13.1±6.5 days). Internalizing symptoms were measured using self-report and rs-FC was measured between the DMN and three neurocognitive networks: dorsal attention network (DAN), frontoparietal network (FPN), and salience network (SN). Associations between sleep timing and rs-FC were measured using linear regressions adjusting for age, sex, race, parental education, family income, puberty, and head motion. Average midpoint of sleep was 3:35 AM (range: 12:34 AM-11:27 PM). Later midpoint of sleep was associated with increased self-reported depressive symptoms. Later midpoint of sleep was associated with lower DMN-DAN rs-FC. There were no associations between midpoint of sleep and DMN-DMN, DMN-FPN, or DMN-SN network rs-FC. These results add to and extend prior studies in youth by incorporating objective measures of sleep timing (Fitbit data), and in a large national sample. Additionally, our findings may have implications for the consideration of sleep timing when designing behavioral-health interventions in youth

Dispersion Relation Bounds for pi pi Scattering

Axiomatic principles such as analyticity, unitarity and crossing symmetry constrain the second derivative of the pi pi scattering amplitudes in some channels to be positive in a region of the Mandelstam plane. Since this region lies in the domain of validity of chiral perturbation theory, we can use these positivity conditions to bound linear combinations of \bar{l}_1 and \bar{l}_2. We compare our predictions with those derived previously in the literature using similar methods. We compute the one-loop pi pi scattering amplitude in the linear sigma model (LSM) using the MS-bar scheme, a result hitherto absent in the literature. The LSM values for \bar{l}_1 and \bar{l}_2 violate the bounds for small values of m_sigma/m_pi. We show how this can occur, while still being consistent with the axiomatic principles.Comment: 12 pages, 8 figures. Two references added, a few minor changes. Published versio

Virtual Medical Board: A Distributed Bayesian Agent Based Approach

Distributed Decision Making has become of increasing importance to get solution of different real life problems, where decision makers are in geographically dispersed locations. Application of agent and multi agent system in this Distributed Decision Support System is an evolving paradigm. One of such real life problem is medical diagnosis. For critical medical diagnosis, medical board is formed which is a coordinative discussion mechanism between a group of expert physicians to diagnose a patient. But always forming a medical board with a group of expert physicians may not be possible due to lack of infrastructure, availability, time etc. In that situation the role of multi agent based distributed decision making can comes into play. In this paper we develop a Virtual Medical Board System in which a number of software agents (expert agents) act as a group of expert physician with knowledge base(KB), reasoning capability. They coordinatively discuss with each other to diagnose a patieh each other to diagnose a patient. We represent the discussion module of the system in the form of Bayesian Network of Bayesian Agent (BNBA). In BNBA each BA is the expert software agent whose Knowledge Base (KB) is represented in the form of Bayesian Network (BN). Also the BDI (Belief, Desire, Intention) model of each BA is represented in this paper

The Zero-Bin and Mode Factorization in Quantum Field Theory

We study a Lagrangian formalism that avoids double counting in effective field theories where distinct fields are used to describe different infrared momentum regions for the same particle. The formalism leads to extra subtractions in certain diagrams and to a new way of thinking about factorization of modes in quantum field theory. In non-relativistic field theories, the subtractions remove unphysical pinch singularities in box type diagrams, and give a derivation of the known pull-up mechanism between soft and ultrasoft fields which is required by the renormalization group evolution. In a field theory for energetic particles, the soft-collinear effective theory (SCET), the subtractions allow the theory to be defined with different infrared and ultraviolet regulators, remove double counting between soft, ultrasoft, and collinear modes, and give results which reproduce the infrared divergences of the full theory. Our analysis shows that convolution divergences in factorization formul\ae occur due to an overlap of momentum regions. We propose a method that avoids this double counting, which helps to resolve a long standing puzzle with singularities in collinear factorization in QCD. The analysis gives evidence for a factorization in rapidity space in exclusive decays.Comment: 92 pages, v4- Journal version. Some improvements to language in sections I, IIA, VI

A Lattice Test of 1/N_c Baryon Mass Relations

1/N_c baryon mass relations are compared with lattice simulations of baryon masses using different values of the light-quark masses, and hence different values of SU(3) flavor-symmetry breaking. The lattice data clearly display both the 1/N_c and SU(3) flavor-symmetry breaking hierarchies. The validity of 1/N_c baryon mass relations derived without assuming approximate SU(3) flavor-symmetry also can be tested by lattice data at very large values of the strange quark mass. The 1/N_c expansion constrains the form of discretization effects; these are suppressed by powers of 1/N_c by taking suitable combinations of masses. This 1/N_c scaling is explicitly demonstrated in the present work.Comment: 13 pages, 20 figures; v2 version to be published in PR

On-Chip Optical Transduction Scheme for Graphene Nano-Electro-Mechanical Systems in Silicon-Photonic Platform

We present a scheme for on-chip optical transduction of strain and displacement of Graphene-based Nano-Electro-Mechanical Systems (NEMS). A detailed numerical study on the feasibility of three silicon-photonic integrated circuit configurations is presented: Mach-Zehnder Interferometer(MZI), micro-ring resonator and ring-loaded MZI. An index-sensing based technique using a Mach-Zehnder Interferometer loaded with a ring resonator with a moderate Q-factor of 2400 can yield a sensitivity of 28 fm/sqrt(Hz), and 6.5E-6 %/sqrt(Hz) for displacement and strain respectively. Though any phase sensitive integrated photonic device could be used for optical transduction, here we show that optimal sensitivity is achievable by combining resonance with phase sensitivity

Gamifying Information System Testing–Qualitative Validation through Focus Group Discussion

This paper presents the evaluation of a developed gamified Information System Testing platform through results obtained from focus group sessions with software developers and testers. The purpose of this study is to understand if the developed tool and platform can help Information System Testing to be interesting while increasing the engagement of software testers in a rewarding testing environment. Findings suggest that choosing suitable game elements to design a gamified environment for performing serious tasks is very important. Moreover, findings suggest that the developed tool and gamification may be a solution to increase testers’ engagement and testing experience. Furthermore, participants suggested that game elements such as feedback and comparison may increase testing motivation, engagement and experience of software testers. The majority of participants rated the feedback element as a vital element in a gamified Information System Testing environment