Sisir Roy

The 'prediction imperative' as the basis for self-awareness

Here, we propose that global brain function is geared towards the implementation of intelligent motricity. Motricity is the only possible external manifestation of nervous system function (other than endocrine and exocrine secretion and the control of vascular tone). The intelligence component of motricity requires, for its successful wheeling, a prediction imperative to approximate the consequences of the impending motion. We address how such predictive function may originate from the dynamic properties of neuronal networks.

Scaling in cosmology and the arrow of time

Cosmological theories and theories of fundamental physics must ultimately not only account for the structure and evolution of the universe, the physics of fundamental interactions but also lead to an understanding of why this particular universe follows the physics that it does. Such theories must lead to an understanding of the values of the fundamental constants themselves. Moreover, the understanding of universe has to utilize experimental data from the present to deduce the state of the universe in distant regions of the past and also account for certain peculiarities or coincidences observed.

Weak value of dwell time for quantum dissipative spin-1/2 systems

The dwell time is calculated within the framework of time dependent weak measurement considering dissipative interaction between a spin half system and the environment. Caldirola and Montaldis method of retarded Schroedinger equation is used to study the dissipative system. The result shows that inclusion of dissipative interaction prevents zero time tunneling.

Bacterial Conversations and Pattern Formation

It has long been recognized that certain bacterial groups exhibit cooperative behavioral patterns. Bacteria accomplish such communication via exchange of extracellular signaling molecules called pheromones(autoinducer or quorum sensing molecules). As the bacterial culture grows, signal molecules are released into extracellular milieu accumulate, changing water fluidity. Under such threshold conditions swimming bacterial suspensions impose a coordinated water movement on a length scale of the order 10 to 100 micrometers compared with a bacterial size of the order of 3 micrometers.Here, we investigate the non-local hydrodynamics of the quorum state and pattern formation using forced Burgers equation with Kwak transformation. Such approach resulted in the conversion of the Burgers equation paradigm into a reaction-diffusion system. The examination of the dynamics of the quorum sensing system, both analytically as well as numerically result in similar long-time dynamical behaviour.

Dissipative Effect and Tunneling Time

The quantum Langevin equation has been studied for dissipative system using the approach of Ford et al. Here, we have considered the inverted harmonic oscillator potential and calculated the effect of dissipation on tunneling time, group delay, and the self-interference term. A critical value of the friction coefficient has been determined for which the self-interference term vanishes. This approach sheds new light on understanding the ion transport at nanoscale.

Non-local hydrodynamics of swimming bacteria and self-activated process

Water fluidity is modified, in a nontrivial manner, by the presence of bacteria above a threshold number density. Under such threshold conditions swimming bacterial suspensions impose a coordinated water movement on a length scale of the order (10–100) micrometers compared with a bacterial size of the order of 3 micrometers. This observation leads to fundamental questions concerning the cell-to-cell communication presently known as quorum sensing. The aim of this paper is to study the quorum state using non-local hydrodynamics. We emphasize that densely packed bacteria may be viewed as ‘bacterial fluid’ or ‘living fluid’ similar to that of dense granular systems. The behaviour of the fluid of granular mass is quite different from that of typical fluids. This granularity imposes a second source of fluctuations because grains cannot be treated as points at any length scale. This type of fluctuation is known as non-local noise in contrast to local noise in usual hydrodynamic flow. The non-local hydrodynamical framework is applied here to consider the effect of non-local noise. In this framework of nonlocal hydrodynamics viscosity is generated by self-induced noise. This viscosity leads the actively moving bacteria into the meta-stable states required to support quorum, given the non-local nature of stresses mediated by autoinducers. The shear stress created non-locally within this framework depending on the non-local noise of granularity and the viscosity associated to the this noise can be tested experimentally. The existence of this kind non-chemical self-induced process may be present not only in cell-to-cell bacteria communication but also in eukaryotic cell-to-cell interactions.

Hartman effect and dissipative quantum systems

The dwell time for dissipative quantum system is shown to increase with barrier width. It clearly precludes Hartman effect for dissipative systems. Here calculation has been done for inverted parabolic potential barrier.

Consciousness as an Inhibited Manifestation and Quantum Physics

The term soul is used in the traditional literature as a synonym for one’s true Self and is associated with the subjective essence of one’s living. Since, we don’t have any means to quantify it, the science has ruled out this idea from its investigations. But, in a recent study, Ceylan et al. (2017) has reintroduced the word soul to scientific literature and examined the possibility of the study of the soul through scientific modalities. The primary focus of their study is to find and understand the scientific analog of the soul as quoted and discussed in the traditional literature. In the present paper, we examine the idea of a soul that uses a novel approach; integrating neuroscience and quantum physics, as proposed in Ceylan et al. (2017). For this purpose, we make use of findings from neuroscientific studies on meditation to understand the concepts of soul and consciousness in terms of inhibition mechanisms. In this context, this paper serves as an attempt to call for more studies to discuss and expand the hypothesis about the soul as uninhibited mental activity.

Bacterial Communication And Relevance Of Quantum Theory

The recent findings confirm that bacteria communicate each other through chemical and electrical signals. Bacteria use chemical signaling molecules which are called as quorum sensing molecules(QSMs) or autoinducers. Moreover, the ion channels in bacteria conduct a long-range electrical signaling within biofilm communities through propagated waves of potassium ions and biofilms attracts other bacterial species too. Both communication process are used by bacteria to make their own survival strategies. In this article, we model this bacterial communication mechanism by complex Ginzburg- Landau equation and discuss the formation of patterns depending on kinematic viscosity associated with internal noise. Again, the potassium wave propagation is described by the non-linear Schrödinger equation in a dissipative environment. By adding perturbation to non-linear Schrödinger equation one arrives at Complex Ginzburg-Landau equation. In this paper we emphasize that at the cellular level(bacteria) we use Complex Ginzburg - Landau equation as a perturbed Nonlinear Schrödinger equation to understand the bacterial communication as well as pattern formation in Biofilms for certain range of kinematic viscosity which can be tested in laboratory experiment. Here, the perturbation is due to the existence of non thermal fluctuations associated to the finite size of the bacteria. It sheds new light on the relevance of quantum formalism in understanding the cell to cell communication.

The role of coherence in bacterial communication

Bacteria within biofilms can coordinate their behavior through distinct from of communication mechanism1. The well-established cell - to - cell signaling process in bacteria is known as quorum sensing through chemical signaling molecules2-5. Recently, another cell- to - cell communication process based on ion channel mediated electrical signaling6 has also been observed. In this article, we propose a novel approach to explain the role of coherence and phase synchronization in the cell – to – cell bacterial communication. The observable long – range coherent electrical signaling is species independent and it is caused by membrane – potential - dependent modulation of tumbling frequency7-9. Moreover, noise can play a constructive role in enhancing the synchronization of chaotic bacterial communication systems and noise associated with the opening and closing the gate of ion channel induce small kinetic viscosity that make a wave-like pattern in concentration profile of quorum sensing.