scholarly journals Description of processes passing at finite space and time intervals in the framework of QFT

2019 ◽  
Vol 222 ◽  
pp. 01009
Author(s):  
Vadim Egorov ◽  
Igor Volobuev
Keyword(s):  
Plane Waves ◽  
Neutral Kaon ◽  
Pion Decay ◽  
Momentum Representation ◽  
Time Intervals ◽  
Final Particle ◽  
New Approach ◽  
Space And Time ◽  
Feynman Rules ◽  
Finite Space

We consider a new approach to the description in the framework of QFT of processes passing at finite space and time intervals. The formalism is based on the Feynman diagram technique in the coordinate representation, in which the rules of passing to the momentum representation are modified in accordance with the experimental setup of neutrino oscillation experiments. In effect, only the propagators of particles in the momentum representation are modified, while all the other standard Feynman rules in the momentum representation remain the same. Since the initial and final particle states are described by plane waves, the approach does not need the use of wave packets, which greatly simplifies the calculations of amplitudes. Taking as examples the processes of displaced pion decay, neutral kaon and neutrino oscillations we show that the approach under consideration correctly reproduces the known standard results.

scholarly journals Quantum field-theoretical descriprion of neutrino oscillations in T2K experiment

2019 ◽  
Vol 222 ◽  
pp. 03002
Author(s):  
Vadim Egorov ◽  
Timofei Rusalev
Keyword(s):  
Neutrino Oscillations ◽  
Plane Waves ◽  
Quantum Field ◽  
Momentum Representation ◽  
Final Particle ◽  
Detector Position ◽  
Electron Production ◽  
Feynman Rules ◽  
Muon Production ◽  
Production Probability

We consider neutrino oscillations in the T2K experiment using a new quantum field-theoretical approach to the description of processes passing at finite space-time intervals. It is based on the Feynman diagram technique in the coordinate representation, supplemented by modified rules of passing to the momentum representation. Effectively this leads to the Feynman propagators in the momentum representation being modified, while the rest of the Feynman rules remain unchanged. The approach does not make use ofwave packets, the initial and final particle states are described by plane waves, which essentially simplifies the calculations. The oscillation fading out due to momentum distribution of the initial particles is taken into account. The obtained results reproduce the predictions of the standard description and confirm that the far detector position corresponds to the first minimum for muon production probability and the first maximum for electron production probability.

scholarly journals Quantum field-theoretical description of neutrino and neutral kaon oscillations

2018 ◽  
Vol 33 (13) ◽  
pp. 1850075 ◽  
Author(s):  
Igor P. Volobuev
Keyword(s):  
Plane Waves ◽  
Neutral Kaon ◽  
Theoretical Description ◽  
Matrix Formalism ◽  
Quantum Field ◽  
Time Intervals ◽  
Standard Quantum ◽  
Mass Eigenstates ◽  
Quantum Mechanical Description ◽  
S Matrix

It is shown that the neutrino and neutral kaon oscillation processes can be consistently described in quantum field theory using only plane waves of the mass eigenstates of neutrinos and neutral kaons. To this end, the standard perturbative S-matrix formalism is modified so that it can be used for calculating the amplitudes of the processes passing at finite distances and finite time intervals. The distance-dependent and time-dependent parts of the amplitudes of the neutrino and neutral kaon oscillation processes are calculated and the results turn out to be in accordance with those of the standard quantum mechanical description of these processes based on the notion of neutrino flavor states and neutral kaon states with definite strangeness. However, the physical picture of the phenomena changes radically: now, there are no oscillations of flavor or definite strangeness states, but, instead of it, there is interference of amplitudes due to different virtual mass eigenstates.

LOCAL ANALYSIS BY WAVELETS VERSUS NONLOCAL FOURIER ANALYSIS

2007 ◽  
Vol 05 (01n02) ◽  
pp. 89-95
Author(s):  
J. R. CROCA
Keyword(s):  
Quantum Mechanics ◽  
Fourier Analysis ◽  
Quantum Physics ◽  
Plane Waves ◽  
Local Analysis ◽  
Mathematical Tool ◽  
Space Harmonic ◽  
New Approach ◽  
Spatial Frequencies ◽  
Temporal And Spatial

Orthodox quantum mechanics has another implicit postulate stating that temporal and spatial frequencies of the Planck–Einstein and de Broglie formulas can only be linked with the infinite, in time and space, harmonic plane waves of Fourier analysis. From this assumption, nonlocality either in space and time follows directly. This is what is called Fourier Ontology. In order to build nonlinear causal and local quantum physics, it is necessary to reject Fourier ontology and accept that in certain cases a finite wave may have a well defined frequency. Now the mathematical tool to describe this new approach is wavelet local analysis. This more general nonlinear local and causal quantum physics, in the limit of the linear approximation, contains formally orthodox quantum mechanics as a particular case.

scholarly journals Spent mushroom substrate: a crucial biosorbent for the removal of ferrous iron from groundwater

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
D. Menaga ◽  
S. Rajakumar ◽  
P. M. Ayyasamy
Keyword(s):  
Ferrous Iron ◽  
Tamil Nadu ◽  
Contaminated Water ◽  
Spent Mushroom Substrate ◽  
Pseudo First Order Reaction ◽  
Time Intervals ◽  
New Approach ◽  
First Order ◽  
Sorption Ability ◽  
Pseudo Second Order

Abstract A new approach was carried out with the spent mushroom substrate (SMS) of Pleurotus florida on ferrous iron (Fe2+) removal using live, dead and pretreated substrate. In this study, the various dosage levels of SMS namely, 0.25, 0.50, 1.0 and 1.50 g/50 mL were used for the removal of Fe2+ at different time intervals for 90 min. The effect of various temperatures and pH on Fe2+ removal was studied with optimized dosages and time intervals. The biosorption potential of P. florida SMS was checked against the iron-contaminated groundwater collected from in and around Salem, Namakkal and Dharmapuri districts of Tamil Nadu. The biosorption data were obtained and analyzed in terms of their kinetic behavior. Among the SMS of P. florida, the live SMS showed potential Fe2+ removal (100%) from aqueous metal solution in all the tested concentrations. SMS of P. florida showed high potential removal of Fe2+ in neutral pH, at room temperature and explored an efficient sorption ability (100%) in the tested water sample (SW10). The adsorption kinetic values fitted very well with pseudo-second-order when comparing with pseudo-first-order reaction. FTIR, SEM and EDX analysis proved the accumulation of Fe2+ by the SMS. The present study confirmed that the live SMS of P. florida may serve as a potential and eco-friendly biosorbent for removal of Fe2+ from the iron-contaminated water. Graphic abstract

CALIFORNIA'S GNOME TRAJECTORY INITIATIVE TO DETERMINE BEST ACHIEVABLE PROTECTION FOR SENSITIVE SHORELINE RESOURCES FROM VESSEL OIL SPILLS

2005 ◽  
Vol 2005 (1) ◽  
pp. 161-165
Author(s):  
Carl Jochums ◽  
Glen Watabyashi ◽  
Heather Parker-Hall
Keyword(s):  
Oil Spill ◽  
Oil Spills ◽  
Oil Pollution ◽  
Time Intervals ◽  
New Approach ◽  
Environmental Consequences ◽  
Playing Field ◽  
Response Planning ◽  
Objective Standard ◽  
Shoreline Protection

ABSTRACT California has initiated a new approach to create an objective standard and regulate best achievable protection (BAP) for sensitive shoreline protection from vessel spills. The Oil Pollution Act (OPA 90) and California's Lempert-Keene-Seastrand Oil Spill Prevention and Response Act (SB 2040) mandate BAP as the standard for preparedness and response. BAP poses the critical response planning questions: “How much response resources should industry provide?” and “In what timeframes should those resources be deployed?” Prior California regulations intended to achieve BAP by relying on vessels to identify hazards, trajectories, environmental consequences, and response resource plans, produced less than optimal results in many instances. Though effective in theory, this approach resulted in fuzzy consequences and vague arrangements for adequate response. Because it was neither clear what sites would be protected (and what response resources would be required) nor at what time, and because it was consequentially not clear what response resources would be engaged to execute protection, drilling C-plans became obtuse. This in turn fostered “paper tiger” OSROs and resulted in an uneven playing field for business competitors. In Californias new approach, OSPR used many of the original concepts to identify BAP by using the NOAA GNOME oil spill model for generic vessel risk threats for California ports and along the California coast. This paper explains the theory, steps, and details. As a result of this process, BAP has been defined in terms of specific site deployments at specific time intervals and presented in tables in regulation. This new approach provides a number of benefits and solutions to the difficult issues in the former approach, including a standard for BAP.

scholarly journals A Mechanism of Variations of the Earth Rotation at Different Timescales

2000 ◽  
Vol 178 ◽  
pp. 373-379
Author(s):  
Yu. V. Barkin
Keyword(s):  
Polar Motion ◽  
Wide Spectrum ◽  
Slow Motion ◽  
Plate Motion ◽  
Triple Junctions ◽  
Geological Time ◽  
Time Intervals ◽  
New Approach ◽  
Mass Redistribution ◽  
Celestial Bodies

AbstractTo explain the observed effects in the Earth’s polar motion, a mechanism of the relative motion of the lower mantle and upper mantle with a boundary at 670 km of depth is proposed. According to the new approach, the Earth’s layers (including separate plates) are considered as nonspherical, heterogeneous celestial bodies, interacting with each other, with the Moon and the Sun and executing a wide spectrum of relative motions in different timescales. The small displacements of the centers of masses of the lower and upper mantles and their relative rotations have here a primary importance. These displacements display themselves at various time scales (from a few months to millions of years), and their manifestations are readily detected in the regularities of the distribution of geological structures as well as in many geodynamical processes. Important regularities of the ordered positions of the plate centers, of their triple junctions, hot spots, systems of fractures and cracks, geographic structures, fields of fossils, etc., are observed as consequences of certain displacements and inclined rotations (Barkin, 1999). At geological time intervals, the slow motion of the layers causes mutually correlated variations of the processes of rifting, spreading, subduction, regressions and transgressions of the sea, of the plate motion, formation and breakdown of super continents, etc. The motions and the accompanying tectonic mass redistribution cause variations of the components of the Earth’s inertia tensor and geopotential, which lead to variations of its diurnal rotation and polar motion. Explanation of the main properties of the perturbed Chandler polar motion has been done.

scholarly journals Neurophysiological coding of space and time in the hippocampus, entorhinal cortex, and retrosplenial cortex

2020 ◽  
Vol 4 ◽  
pp. 239821282097287
Author(s):  
Andrew S. Alexander ◽  
Jennifer C. Robinson ◽  
Holger Dannenberg ◽  
Nathaniel R. Kinsky ◽  
Samuel J. Levy ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Entorhinal Cortex ◽  
Neuronal Response ◽  
Retrosplenial Cortex ◽  
Movement Direction ◽  
Head Direction ◽  
Time Intervals ◽  
Running Speed ◽  
Space And Time ◽  
Spatiotemporal Trajectories

Neurophysiological recordings in behaving rodents demonstrate neuronal response properties that may code space and time for episodic memory and goal-directed behaviour. Here, we review recordings from hippocampus, entorhinal cortex, and retrosplenial cortex to address the problem of how neurons encode multiple overlapping spatiotemporal trajectories and disambiguate these for accurate memory-guided behaviour. The solution could involve neurons in the entorhinal cortex and hippocampus that show mixed selectivity, coding both time and location. Some grid cells and place cells that code space also respond selectively as time cells, allowing differentiation of time intervals when a rat runs in the same location during a delay period. Cells in these regions also develop new representations that differentially code the context of prior or future behaviour allowing disambiguation of overlapping trajectories. Spiking activity is also modulated by running speed and head direction, supporting the coding of episodic memory not as a series of snapshots but as a trajectory that can also be distinguished on the basis of speed and direction. Recent data also address the mechanisms by which sensory input could distinguish different spatial locations. Changes in firing rate reflect running speed on long but not short time intervals, and few cells code movement direction, arguing against path integration for coding location. Instead, new evidence for neural coding of environmental boundaries in egocentric coordinates fits with a modelling framework in which egocentric coding of barriers combined with head direction generates distinct allocentric coding of location. The egocentric input can be used both for coding the location of spatiotemporal trajectories and for retrieving specific viewpoints of the environment. Overall, these different patterns of neural activity can be used for encoding and disambiguation of prior episodic spatiotemporal trajectories or for planning of future goal-directed spatiotemporal trajectories.

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