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Journal of Modern Physics 2012年第1期3卷 110-115页

作者： Usha kulshreshtha daya shankar kulshreshtha 不详

Recently we have studied the instant-form quantization (IFQ) and the light-front quantization (LFQ) of the conformally gauge-fixed Polyakov D1 brane action using the Hamiltonian and path integral formulations. The IFQ is studied in the equal world-sheet time framework on the hyperplanes defined by the world- sheet time σ0 = τ = constant and the LFQ in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time . The light-front theory is seen to be a constrained system in the sense of Dirac in contrast to the instant-form theory. However, owing to the gauge anomalous nature of these theories, both of these theories are seen to lack the usual string gauge symmetries defined by the world-sheet reparametrization invariance (WSRI) and the Weyl invariance (WI). In the present work we show that these theories when considered in the presence of background gauge fields such as the NSNS 2-form gauge field or in the presence of gauge field and the constant scalar axion field , then they are seen to possess the usual string gauge symmetries (WSRI and WI). In fact, these background gauge fields are seen to behave as the Wess-Zumino/Stueckelberg fields and the terms containing these fields are seen to behave as Wess-Zumino or Stueckelberg terms for these theories.

关键词： Light-Front Quantization Hamiltonian Quantization Path Integral Quantization Constrained Dynamics Constraint Quantization Gauge Symmetry String Gauge Symmetry String Theory D-Brane Actions Polyakov Action Light-Cone Quantization

Light-Front Hamiltonian and Path Integral Formulations of the Conformally Gauge-Fixed Polyakov D1 Brane Action with a Scalar Dilation Field

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Journal of Modern Physics 2011年第5期2卷 826-833页

作者： Usha kulshreshtha daya shankar kulshreshtha 不详

Recently we have studied the instant-form quantization (IFQ) of the conformally gauge-fixed Polyakov D1 brane action with and without a scalar dilaton field using the Hamiltonian and path integral formulations in the equal world-sheet time framework on the hyperplanes defined by the world- sheet time σ0=τ=constant . The light-front quantization (LFQ) of this theory without a scalar dilaton field has also been studied by us recently. In the present work we study the LFQ of this theory in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time σ+=τ+σ=constant , using the Hamiltonian and path integral formulations. The light-front theory is seen to be a constrained system in the sense of Dirac. The light-front theory is seen to possess a set of twenty seven primary second-class contraints. In the present work Hamiltonian and path integral quantizations of this theory are studied on the light-front.

关键词： Light-Front Quantization Hamiltonian Quantization Path Integral Quantization Constrained Dynamics Constraint Quantization Gauge Symmetry String Gauge Symmetry String Theory D-brane Actions Polyakov Action Light-Cone Quantization

Light-Front Hamiltonian, Path Integral and BRST Formulations of the Chern-Simons Theory under Appropriate Gauge-Fixing

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Journal of Modern Physics 2010年第6期1卷 385-392页

作者： Usha kulshreshtha daya shankar kulshreshtha James P. Vary 不详

The Chern-Simons theory in two-space one-time dimensions is quantized on the light-front under appropriate gauge-fixing conditions using the Hamiltonian, path integral and BRST formulations.

关键词： Hamiltonian Quantization Path Integral Quantization BRST Quantization Chern-Simons Theories Light-Cone Quantization Light-Front Quantization Constrained Dynamics Quantum Electrodynamics Models in Lower Dimensions

Hamiltonian, Path Integral and BRST Formulations of the Restricted Gauge Theory of <i>QCD<sub>2</sub></i>

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Journal of Modern Physics 2018年第14期9卷 2355-2369页

作者： Usha kulshreshtha daya shankar kulshreshtha James P. Vary Department of Physics Kirori Mal College University of Delhi Delhi India Department of Physics and Astrophysics University of Delhi Delhi India Department of Physics and Astronomy Iowa State University Ames Iowa USA

We study the Hamiltonian, path integral and Becchi-Rouet-Stora and Tyutin (BRST) formulations of the restricted gauge theory of QCD2 à la Cho et al. under appropriate gauge-fixing conditions.

关键词： Hamiltonian Quantization Path Integral Quantization BRST Quantization Quantum Chromodynamics QCD2 Field Theories in Lower Dimensions Gauge-Invariant Theories Gauge-Fixing

Comparative measurement of CO_(2),CH_(4)and CO at two traffic interjunctions having inflated vehicular flow in Delhi

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Journal of Environmental Sciences 2024年第7期141卷 314-329页

作者： Komal daya Soni Khem Singh shankar G.Aggarwal CSIR-National Physical Laboratory Dr.K.S.Krishnan MargNew Delhi 110012India Academy of Scientific&Innovative Research(AcSIR) Ghaziabad 201002India

Vehicular emissions are considered one of the major anthropogenic sources of greenhouse gases and poor air quality in metropolitan *** study aims to see the correlation of CO_(2),CH_(4),and CO through monitoring over a period from December 2020 to October 2021 covering three seasons’winter,summer,and monsoon at two different traffic locations of Delhi having different traffic volumes,road patterns,and traffic *** annual average morning concentration of CO_(2),CH_(4)and CO was found(533±105),(7.3±3.1),(10.7±3.0)ppm at Najafgarh and(480±70),(5.2±1.8),(7.8±2.8)ppm at Rajendra Place,respectively.A relationship between concentration of all three gases and meteorological parameters such as temperature,humidity,wind speed and wind direction has also been investigated using Pearson correlation coefficient and pollution rose diagram.A comparable pattern in concentration was observed for all three gases in spatial(location)and temporal(diurnal)*** concentration trend of CO_(2)in different seasons is winter>summer>monsoon,while in the case of CH_(4)winter=summer>monsoon but not any seasonal trend was noted in CO *** is observed that CO_(2)has a good relation with CO(a tracer for vehicular emission)in terms of diurnal variation,whereas,CH_(4)does not represent a relation with CO and CO_(2)diurnally,suggesting that vehicles are the source of CO_(2)but not much contributing to other greenhouse gases like CH_(4).

关键词： Vehicular emission Greenhouse gases Harmful pollutants Meteorological parameters

Ground Rupturing Due to Entrapped Air/Gas in the Unconfined Zone

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International Journal of Geosciences 2010年第3期1卷 149-154页

作者： Manas Banerjee Vimla Prasad Singh Hridaya Narain Singh daya shankar Sun jay Uma Shanker Singh 不详

The sudden and large oscillation of pressure of compressed air/gas entrapped in porous medium due to the changes in the actual pore-fluid pressure, during recharge of water following intense rainfall after a prolonged period of dryness such that the rainfall intensity exceeding infiltration capacity, leads to the generation of hydo-tremors. These hydro-tremors cause ground rupturing, subsidence, developments of cracks in the building, etc. A theoretical model has been presented to estimate the successive values of compressed air/gas pressures due to the successive development of actual pore-fluid pressures and effective stresses during recharge of water of the unconfined zone during the onset of the summer monsoon of 2008 in the northern parts of India.

关键词： Unconfined Zone Compressed Air/Gas Pore-Fluid Pressure Hydro-Tremor Ground Rupturing Effective Stress