Pinaki Patra
@bkcc.ac.in
Assistant Professor
Brahmananda Keshab Chandra College
EDUCATION
B.Sc., M.Sc. and Ph.D in Physics.
RESEARCH, TEACHING, or OTHER INTERESTS
Mathematical Physics, Nuclear and High Energy Physics, Statistical and Nonlinear Physics, Applied Mathematics
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Pinaki Patra
AIP Publishing
With the help of the generalized Peres–Horodecki separability criterion (Simon’s condition) for a bipartite Gaussian state, we have studied the separability of the noncommutative (NC) space coordinate degrees of freedom. Non-symplectic nature of the transformation between the usual commutative space and NC space restricts the straightforward use of Simon’s condition in NCS. We have transformed the NCS system to an equivalent Hamiltonian in commutative space through the Bopp shift, which enables the utilization of the separability criterion. To make our study fairly general and to analyze the effect of parameters on the separability of bipartite state in NC-space, we have considered a bilinear Hamiltonian with time-dependent (TD) parameters, along with a TD external interaction, which is linear in field modes. The system is transformed (Sp(4,R)) into canonical form keeping the intrinsic symplectic structure intact. The solution of the TD-Schrödinger equation is obtained with the help of the Lewis–Riesenfeld invariant method (LRIM). Expectation values of the observables (thus the covariance matrix) are constructed from the states obtained from LRIM. It turns out that the existence of the NC parameters in the oscillator determines the separability of the states. In particular, for isotropic oscillators, the separability condition for the bipartite Gaussian states depends on specific values of NC parameters. Moreover, particular anisotropic parameter values for the oscillator may cease the separability. In other words, both the deformation parameters (θ, η) and parameter values of the oscillator (mass, frequency) are important characteristics for the separability of bipartite Gaussian states. Thus tuning the parameter values, one can destroy or recreate the separability of states. With the help of a toy model, we have demonstrated how the tuning of a TD-NC space parameter affects the separability.
Pinaki Patra
Springer Science and Business Media LLC
Shilpa Nandi, Muklesur Rahaman, and Pinaki Patra
World Scientific Pub Co Pte Ltd
In this paper, we investigate the quantum entanglement induced by phase-space noncommutativity. Both the position–position and momentum–momentum noncommutativity are incorporated to study the entanglement properties of coordinate and momentum degrees of freedom under the shade of oscillators in noncommutative space. Exact solutions for the systems are obtained after the model is re-expressed in terms of canonical variables, by performing a particular Bopp’s shift to the noncommuting degrees of freedom. It is shown that the bipartite Gaussian state for an isotropic oscillator is always separable. To extend our study for the time-dependent system, we allow arbitrary time dependency on parameters. The time-dependent isotropic oscillator is solved with the Lewis–Riesenfeld invariant method. It turns out that even for arbitrary time-dependent scenarios, the separability property does not alter. We extend our study to the anisotropic oscillator, which provides an entangled state even for time-independent parameters. The Wigner quasi-probability distribution is constructed for a bipartite Gaussian state. The noise matrix (covariance matrix) is explicitly studied with the help of Wigner distribution. Simon’s separability criterion (generalized Peres–Horodecki criterion) has been employed to find the unique function of the (mass and frequency) parameters, for which the bipartite states are separable. In particular, we show that the mere inclusion of non-commutativity of phase-space is not sufficient to generate the entanglement, rather anisotropy is important at the same footing. We explore the experimental viability of our result through the computation of extractable work for the current situation.
Pinaki Patra
AIP Publishing
A charged harmonic oscillator in a magnetic field, Landau problems, and an oscillator in a noncommutative space share the same mathematical structure in their Hamiltonians. We have considered a two-dimensional anisotropic harmonic oscillator with arbitrarily time-dependent parameters (effective mass and frequencies), placed in an arbitrarily time-dependent magnetic field. A class of quadratic invariant operators (in the sense of Lewis and Riesenfeld) have been constructed. The invariant operators (Î) have been reduced to a simplified representative form by a linear canonical transformation [the group Sp(4,R)]. An orthonormal basis of the Hilbert space consisting of the eigenvectors of Î is obtained. In order to obtain the solutions of the time-dependent Schrödinger equation corresponding to the system, both the geometric and dynamical phase-factors are constructed. A generalized Peres–Horodecki separability criterion (Simon’s criterion) for the ground state corresponding to our system has been demonstrated.
Pinaki Patra
Springer Science and Business Media LLC
Pinaki Patra, Aditi Chowdhury, and Milan Jana
Springer Science and Business Media LLC
P Patra, J P Saha, and K Biswas
Springer Science and Business Media LLC
K Biswas, J P Saha, and P Patra
Springer Science and Business Media LLC
Kalpana Biswas, Jyoti Prasad Saha, and Pinaki Patra
Springer Science and Business Media LLC
A Rai, P N Potukuchi, P Patra, G K Chaudhari, S S K Sonti, J Karmakar, B Karmakar, A Sharma, D S Mathuria, A Pandey,et al.
IOP Publishing
Systematic studies have been performed on the effect of the surface processing techniques for improving accelerating gradients in superconducting niobium quarter wave resonators (QWR). These include high pressure rinsing (HPR), high temperature heat treatment of cavities and helium pulse processing. Tests done after HPR have not only shown a reduction in field emission in the cavities at high accelerating gradients but also an improvement in the low field quality factor (Q). The effect of the high temperature (650 °C) heat treatment of jacketed QWRs (QWR with the outer helium vessel) on the cavity gradients has also been investigated. This was performed for two different QWR designs and a substantial improvement in performance has been observed in both the cases. The increase in gradients is beyond that due to hydrogen degassing alone. Helium pulse processing during 4 K tests has been tried out on several cavities and its effect on the quality factor at both high and low gradients has been observed. This technique has been found to be useful for those resonators which have a high Q at lower fields but are limited due to the field emission at higher gradients. They have exhibited a marked improvement in the high field Q-slope over and above that obtained with conventional pulse processing under high vacuum. A comprehensive overview of all these developments carried out over the past few years has been reported.
S. Ghosh, V. Joshi, J. Urakawa, N. Terunuma, A. Aryshev, S. Fukuda, M. Fukuda, B.K. Sahu, P. Patra, S.R. Abhilash,et al.
Elsevier BV
Subhendu Ghosh, T. Rao, B. Sahu, B. Karmakar, S. Tripathi, Sunil Kumar, U. Lehnert, Arun Kumar Pandey, D. Kabiraj, S. Fukuda,et al.
The first phase of the pre-bunched Free Electron Laser (FEL) based on the RF electron gun, has been initiated at Inter University Accelerator Centre (IUAC), New Delhi. The photoinjector-based electron gun made from OFHC copper was fabricated and tested with low power RF. The beam optics calculation by using ASTRA and GPT codes are performed and radiation produced from the pre-bunched electron bunches are being calculated. The high-power RF system was ordered and will be commissioned at IUAC by the beginning of 2018. The design of the laser system is being finalised and assembly/testing of the complete laser system will be started soon in collaboration with KEK, Japan. The initial design of the photocathode deposition system has been completed and its procurement/de-velopment process is also started. The first version of the undulator magnet design is completed and its further im-provements are underway. The initial design of the DLS beam line have been worked out and various beam diag-nostics components are being finalised. Production
B.K. Sahu, R. Ahuja, Rajesh Kumar, S.K. Suman, D.S. Mathuria, A. Rai, P. Patra, A. Pandey, J. Karmakar, G.K. Chowdhury,et al.
Elsevier BV
P Patra and J P Saha
Springer Science and Business Media LLC
Pinaki Patra, Md. Raju, Gargi Manna, and Jyoti Prasad Saha
Hindawi Limited
The Ostrogradski approach for the Hamiltonian formalism of higher derivative theory is not satisfactory because the Lagrangian cannot be viewed as a function on the tangent bundle to coordinate manifold. In this paper, we have used an alternative approach which leads directly to the Lagrangian which, being a function on the tangent manifold, gives correct equation of motion; no new coordinate variables need to be added. This approach can be used directly to the singular (in Ostrogradski sense) Lagrangian. We have used this method for the Regge-Teitelboim (RT) minisuperspace cosmological model. We have obtained the Hamiltonian of the dynamical equation of the scale factor of RT model.
PINAKI PATRA, TANMAY MANDAL, and JYOTI PRASAD SAHA
Springer Science and Business Media LLC
Trina Chakraborty, Manik Banik, and Pinaki Patra
Springer Science and Business Media LLC
Biplab Pal, Pinaki Patra, Jyoti Prasad Saha, and Arunava Chakrabarti
American Physical Society (APS)
We present an exact analytical method of engineering the localization of electromagnetic waves in a fractal waveguide network. It is shown that, a countable infinity of localized electromagnetic modes with a multitude of localization lengths can exist in a Vicsek fractal geometry built with diamond shaped monomode waveguides as the 'unit cells'. The family of localized modes form clusters of increasing size. The length scale at which the onset of localization for each mode takes place can be engineered at will, following a well defined prescription developed within the framework of a real space renormalization group. The scheme leads to an exact evaluation of the wave vector for every such localized state, a task that is non-trivial, if not impossible for any random or deterministically disordered waveguide network.
PINAKI PATRA, ABHIJIT DUTTA, and JYOTI PRASAD Saha
Springer Science and Business Media LLC
T.S. Datta, S. Ghosh, J. Antony, S. Babu, J. Chacko, A. Choudhury, G.K. Choudhuri, D. Kanjilal, S. Kar, M. Kumar,et al.
Elsevier BV
S. Ghosh, R. Mehta, G. K. Chowdhury, A. Rai, P. Patra, B. K. Sahu, A. Pandey, D. S. Mathuria, J. Chacko, A. Chowdhury,et al.
American Physical Society (APS)
A superconducting linear accelerator based on niobium quarter wave resonators has recently become operational to boost the energy of the heavy ion beams available from the existing 15 UD (unit doubled) Pelletron accelerator. The niobium resonators typically performed at an accelerating field of $3\\char21{}6\\text{ }\\text{ }\\mathrm{MV}/\\mathrm{m}$ at 6 watts of input power in the test cryostat. When they were tested in the linac cryostat, the accelerating fields were drastically reduced and a number of other problems were also encountered. At present, all the problems have been diagnosed and solved. Many design modifications, e.g., in power coupler, mechanical tuner, helium cooling system, etc. were incorporated to solve the problems. A novel method of vibration damping was also implemented to reduce the effect of microphonics on the resonators. Finally, the accelerated beam through linac was delivered to conduct experiments.