Qft Research Papers - Academia.edu (original) (raw)

Quantum Field Theory (QFT) posits that there are several fields (electro-magnetic, gravitational, Higgs) that permeate space throughout the universe. A disturbance in one of those fields causes a wave of energy to be generated. In the... more

Quantum Field Theory (QFT) posits that there are several fields (electro-magnetic, gravitational, Higgs) that permeate space throughout the universe. A disturbance in one of those fields causes a wave of energy to be generated. In the QFT view, everything we see and experience is a wave that is spread out like a cloud – there are no particles with a fixed location in space and a distinct boundary. The author of this paper aims at unifying particles and waves, matter and energy. This unification is suggested in Einstein’s famous formula, E=MC2 and deBroglie’s matter-wave theory. A particle of matter is defined as compressed energy that has a definite locality and involves inherently high potential energy but lower kinetic energy. A wave of energy is defined as a rhythmic high speed, fine particles which are spread out like a cloud without a distinct location and firm boundaries. Such a unification shows how quantum energy can make the transformation from waves to particles, energy to matter, from micro to macro matter and from quantum to classical. The transition from energy to matter can be seen in the various states of matter from quanta to plasma to gas to liquid to solid. If E=MC2 is correct, then the basic unit of mattergy (matter-energy) is the quantum. Perhaps this is what Democritus had in mind when he envisioned the indivisible unit of matter.

Matter/antimatter (MAM) pair production from the vacuum through intense electric fields has been investigated theoretically for nearly a century 1. This presentation will review this history and will examine proposals of MAM for... more

Matter/antimatter (MAM) pair production from the vacuum through intense electric fields has been investigated theoretically for nearly a century 1. This presentation will review this history and will examine proposals of MAM for intra-solar system and interstellar propulsion systems. The quantum mechanical foundation of MAM production was developed by F. Sauter et al. in the 1930's and then placed on a sound quantum electromagnetics (QED) basis by J. Schwinger in 1951. Pair production occurs when the electric field strength E 0 is above the critical value at which the fields become non-linear with self-interactions (known as the Schwinger limit). As the energy density of lasers approach the critical strength of E 0 ~ 10 16 V/cm, the feasibility and functionality of electron-positron pair production has received growing interest. Current laser intensities are approaching within 1 order of magnitude of the Schwinger limit. Physical processes for lowering the critical energy density below the Schwinger limit (and simultaneously enhancing the pair production above the Schwinger limit) through additional quantum mechanical effects have been explored. One under study at the U. of Connecticut and the U. of Duisburg-Essen is pulsation of inhomogeneous electric fields within a carrier wave. Another is via enhancement of quantum effects by addition of a magnetic field B parallel to the electric field E. Magnetic field enhancement to quark/anti-quark production through chiral symmetry breaking effects in quantum chromodynamics (QCD) was investigated theoretically by J. Preskill at Caltech in the 1980's. S. Pyo and D. Page showed in 2007 that parallel magnetic fields also enhance electron/positron production via an analogous QED effect, with enhancement going predominantly as a linear function of B 0 /E 0 , Particle/antiparticle pair production as a highly efficient fuel source for intra solar system and interstellar propulsion was proposed by D. Crow in 1983. The viability of this method of propulsion will be studied, especially from the parallel electric and magnetic field approach. 1 Particle/anti-particle pair production does not (and cannot) take energy from the spacetime vacuum. Rather the energy is drawn from the external electric (and magnetic) fields. This process is very analogous to particle production near the event horizon of a black hole, which reduces the mass of the black hole accordingly. (The primary difference between the two processes is, while both particle and antiparticle are produced from a virtual pair by the electric (and magnetic) fields, only one particle in an initially virtual pair escapes from a black hole (as Hawking radiation) and the antiparticle is captured by the black hole.)

This paper pursues a quantitative feedback theory (QFT) approach to robust controller design for series resonant DC/DC converters. The model is derived using the generalized averaging procedure and the design approach explicitly reveals... more

This paper pursues a quantitative feedback theory (QFT) approach to robust controller design for series resonant DC/DC converters. The model is derived using the generalized averaging procedure and the design approach explicitly reveals the tradeoffs involved in the controller synthesis. A nonlinear model is used to verify the performance of the compensator under several load transients

Motivated by the possibility of a string landscape, we re-examine tunneling of a scalar field across single/multiple barriers. Recent investigations have suggested modifications to the usual picture of false vacuum decay that leads to... more

Motivated by the possibility of a string landscape, we re-examine tunneling of a scalar field across single/multiple barriers. Recent investigations have suggested modifications to the usual picture of false vacuum decay that leads to efficient and rapid tunneling in the landscape when certain conditions are met. This can be due to stringy effects (e.g. tunneling via the DBI action), or effects arising from the presence of multiple vacua (e.g. resonance tunneling). In this paper we discuss both DBI tunneling and resonance tunneling. We provide a QFT treatment of resonance tunneling using the Schrödinger functional approach. We also show how DBI tunneling for supercritical barriers can naturally lead to conditions suitable for resonance tunneling. We argue, using basic ideas from percolation theory, that tunneling can be rapid in a landscape where a typical vacuum has multiple decay channels, and discuss various cosmological implications. This rapidity vacuum decay can happen even if...

Detecting latent tubercular infection (LTBI) in sarcoidosis has important treatment implications. Traditionally tuberculin skin test (TST) is relied upon for this purpose. However, sarcoidosis is known to produce tuberculin anergy, which... more

Detecting latent tubercular infection (LTBI) in sarcoidosis has important treatment implications. Traditionally tuberculin skin test (TST) is relied upon for this purpose. However, sarcoidosis is known to produce tuberculin anergy, which is not affected by high prevalence of tuberculosis (TB) infection. Interferon gamma release assays (IGRAs) have a higher sensitivity and specificity for detecting Mycobacterium tuberculosis (MTB) infection than the conventional TST as they utilize antigens specific for MTB complex. However, there is limited data regarding the performance of these tests in sarcoidosis, particularly in a setting of high population prevalence of LTBI. Herein, we studied the utility of IGRAs in the diagnostic work up of patients with sarcoidosis. Prospectively enrolled, biopsy-confirmed, glucocorticoid naive cases of pulmonary sarcoidosis; pulmonary and extrapulmonary TB; and, healthy controls underwent TST using 0.1 mL (1 tuberculin unit) of purified protein derivative...

In this paper, a fragile watermarking based on two-dimensional Separable Discrete Hartley Transform has been proposed for color image authentication (FWSDHTCIA). Two dimensional SDHT is applied on each 2 × 2 sub-image block of the carrier... more

In this paper, a fragile watermarking based on two-dimensional Separable Discrete Hartley Transform has been proposed for color image authentication (FWSDHTCIA). Two dimensional SDHT is applied on each 2 × 2 sub-image block of the carrier image in row major order and produces four frequency components in transform domain. Due to the high sensitivity of human eye on green channel, only one authenticating message/image bit is fabricated at the second bit position of each frequency component for every 2 × 2 green sub-matrix. Unlikely, in every 2 × 2 red and blue sub-matrices, two bits from the authenticating message/image are fabricated at the second and third bit position of each frequency component as the human eye is less sensitive on red and blue channels as compared to green. After fabricating the authenticating watermark (message/image), a frequency adjustment strategy has been applied to get back the less distorted watermarked image in spatial domain. A delicate re-adjustment has been incorporated in the first frequency component of each 2 × 2 mask, to keep the quantum value positive in spatial domain without hampering the authenticating watermark bits. Two dimensional inverse SDHT (ISDHT) is applied on each 2 × 2 sub-mask as post embedding operation to produce the watermarked image. At the receiving end reverse operation is performed to extract the stream which is compared to the original stream for authentication. Experimental results conform that the proposed algorithm has improvised the payload and PSNR values over SDHTIWCIA [7] scheme which is previously proposed by us. Also, the proposed FWSDHTCIA scheme produces much better result than the Discrete Cosine Transform (DCT), Quaternion Fourier Transformation (QFT) and Spatio-Chromatic DFT (SCDFT) based techniques.

A method to design simple linear controllers for mildly nonlinear systems is presented. In order to design the desired controller we approximate the behavior of the nonlinear system with a set of linear systems which are derived through... more

A method to design simple linear controllers for mildly nonlinear systems is presented. In order to design the desired controller we approximate the behavior of the nonlinear system with a set of linear systems which are derived through linearizations. Classical local linearization is carried out around stationary points but in order to have a better approximation of the nonlinear system selected non-stationary points are taken into account as well. This set of linear models are considered as an uncertainty description for a nominal plant. Quantitative Feedback theory (QFT) may be used to guarantee specification to be fulfilled for all linear models in such an uncertainty set. Traditionally QFT design is carried out in a Nichols diagram by loop shaping of the nominal linear plant. This task highly depends on the experience of the designer and is difficult for unstable systems. In order to facilitate this task an optimization algorithm based on Genetic algorithm is used to automatica...