On the Applications of a New Technique to Solve Linear Differential Equations, with and without Source

A general method for solving linear differential equations of arbitrary order, is used to arrive at new representations for the solutions of the known differential equations, both without and with a source term. A new quasi-solvable potential has also been constructed taking recourse to the above method.Comment: This is a contribution to the Vadim Kuznetsov Memorial Issue on Integrable Systems and Related Topics, published in SIGMA (Symmetry, Integrability and Geometry: Methods and Applications) at http://www.emis.de/journals/SIGMA

India, Vietnam in the Indo-Pacific: A Unifying Construct

Is Indo-Pacific the one overarching forum, evolving from a geopolitical imagination that can bring the two countries closer? If itbe so, then what are the avenues and possibilities that exist in the Indo-Pacific sphere for India and Vietnam, and what are the benefits and drawbacks of subscription to such a concept? Will it be feasible enough to sustain the aspirations as well as concerns of the two countries or there is a need for returning back to basics, and entrusting ASEAN with the centrality which is required for peace and security in the larger Asia-Pacific region. Is China a necessary evil or is it being demonised by the western media? What could be the contours of the evolving geopolitical order when alternatives such as BRICS, SCO, and Asian Infrastructure Investment Bank have been getting attention and subscription from countries across Europe, Africa, and Asia? Has regionalism lost sheen and bilateralism is the only way to deal with larger security and political issues. This paper would address these issues and look for possibilities with regard to India and Vietnam cooperating in the geo-political, and geo-strategic construct which is now known as Indo-Pacific

India, Vietnam in the Indo-Pacific: A Unifying Construct

Is Indo-Pacific the one overarching forum, evolving from a geopolitical imagination that can bring the two countries closer? If itbe so, then what are the avenues and possibilities that exist in the Indo-Pacific sphere for India and Vietnam, and what are the benefits and drawbacks of subscription to such a concept? Will it be feasible enough to sustain the aspirations as well as concerns of the two countries or there is a need for returning back to basics, and entrusting ASEAN with the centrality which is required for peace and security in the larger Asia-Pacific region. Is China a necessary evil or is it being demonised by the western media? What could be the contours of the evolving geopolitical order when alternatives such as BRICS, SCO, and Asian Infrastructure Investment Bank have been getting attention and subscription from countries across Europe, Africa, and Asia? Has regionalism lost sheen and bilateralism is the only way to deal with larger security and political issues. This paper would address these issues and look for possibilities with regard to India and Vietnam cooperating in the geo-political, and geo-strategic construct which is now known as Indo-Pacific

Coherent control of atomic excitation using off-resonant strong few-cycle pulses

We study the dynamics of a two-level system driven by an off-resonant few-cycle pulse which has a phase jump $\phi$ at $t=t_{0}$, in contrast to many cycle pulses, under non rotating-wave approximation (NRWA). We give a closed form analytical solution for the evolution of the probability amplitude $|C_{a} (t)|$ for the upper level. Using the appropriate pulse parameters like phase-jump $\phi$, jump time $t_{0}$, pulse width $\tau$, frequency $\nu$ and Rabi frequency $\Omega_{0}$ the population transfer, after the pulse is gone, can be optimized and for the pulse considered here, enhancement of $10^{6}-10^{8}$ factor was obtained.Comment: 5 Pages, 7 Figure

Effective unidirectional pumping for steady-state amplification without inversion

We discuss an opportunity to achieve amplification without inversion in three-level cascade scheme using an effective unidirectional pumping via bidirectional incoherent pump. Analytical solution to the population and the coherence are obtained in the steady-state regime. With a proper choice of the parameters, obtained here, the possibility for amplification without inversion is presented.Comment: 8 Pages, 7 figure

Experimental observation of carrier-envelope phase effects by multicycle pulses

We present an experimental and theoretical study of carrier-envelope phase (CEP) effects on the population transfer between two bound atomic states interacting with pulses consisting of many cycles. Using intense radio-frequency pulse with Rabi frequency of the order of the atomic transition frequency, we investigated the influence of CEP on the control of phase dependent multi-photon transitions between the Zeeman sub-levels of the ground state of $^{87}$Rb. Our scheme has no limitation on the duration of the pulses. Extending the CEP control to longer pulses creates interesting possibilities to generate pulses with accuracy that is better then the period of optical oscillations.Comment: 8 Pages, 6 Figure

Engineering valley quantum interference in anisotropic van der Waals heterostructures

In this paper, we present a novel route to manipulate the spontaneous valley coherence in two-dimensional valleytronic materials interfaced with other layered materials hosting anisotropic polaritonic modes. We propose two implementations—one, using anisotropic plasmons in phosphorene and another with hyperbolic phonon polaritons in α−MoO₃. In particular, we show the electrostatic tunability of the spontaneous valley coherence achieving robust valley coherence values in the near-infrared wavelengths at room temperature. The tunability of this valley coherence shown in these heterostructures would enable the realization of active valleytronic quantum circuitry