arXiv subjects

Souvik Sarkar

Publications and source records attributed to Souvik Sarkar.

5 recordsLinked to original sources

arXiv2026

BlockRaFT: A Distributed Framework for Fault-Tolerant and Scalable Blockchain Nodes

Blockchain technology enhances transparency by maintaining a distributed ledger among mutually untrusting parties. Despite its advantages, scalability and availability remain critical bottlenecks that hinder widespread adoption. The increasing complexity of blockchain nodes further necessitates robust fault tolerance and high throughput to ensure seamless operations. We present BlockRaFT, a crash-tolerant distributed framework designed to improve both the scalability and reliability of blockchain node operations. BlockRaFT framework utilizes RAFT consensus protocol to elect a leader within a cluster of systems. The elected leader coordinates and distributes workloads across follower nodes, thereby optimizing resource utilization and work load balancing. We analyzed the tasks performed by blockchain nodes and partition them according to their stateful and stateless characteristics. Stateless operations are centralized at the leader, while stateful operations are replicated and coordinated across the cluster to ensure consistency and fault tolerance. We evaluate whether this distributed intra-node architecture provides measurable benefits over traditional single-node execution models in terms of scalability, availability, and performance. Additionally, we introduce a concurrent Merkle tree optimization that decouples smart contract execution from tree updates, significantly reducing one of the significant performance overheads in blockchain systems. Our design philosophy is rooted in utilizing the well-established principles of distributed computing and customizing them for the blockchain domain rather than reinventing them.

cs.DC↗

arXiv2018

Gravitationally Bound Bose Condensates with Rotation

We develop a self-consistent, Gravitoelectromagnetic (GEM) formulation of a slowly rotating, self-gravitating and dilute Bose-Einstein condensate (BEC), intended for astrophysical applications in the context of dark matter halos. GEM self-consistently incorporates the effects of frame dragging to lowest order in $v/c$ via the Gravitomagnetic field. BEC dark matter has attracted attention as an alternative to Cold dark matter (CDM) and Warm dark matter (WDM) for some time now. The BEC is described by the Gross-Pitaevskii-Poisson (GPP) equation with an arbitrary potential allowing for either attractive or repulsive interactions. Owing to the difficulty in obtaining exact solutions to the GEM equations of motion without drastic approximations, we employ the variational method to examine the conditions under which rotating condensates, stable against gravitational collapse, may form in models with attractive and repulsive quartic interactions. We also describe the approximate dynamics of an imploding and rotating condensate by employing a collective coordinate description in terms of the condensate radius.

astro-ph.GA↗

arXiv2017

Canonical Chern-Simons Gravity

We study the canonical description of the axisymmetric vacuum in 2+1 dimensional gravity, treating Einstein's gravity as a Chern Simons gauge theory on a manifold with the restriction that the dreibein is invertible. Our treatment is in the spirit of Kucha\v r's description of the Schwarzschild black hole in 3+1 dimensions, where the mass and angular momentum are expressed in terms of the canonical variables and a series of canonical transformations are performed that turn the curvature coordinates and their conjugate momenta into new canonical variables. In their final form, the constraints are seen to require that the momenta conjugate to the Killing time and curvature radius vanish and what remains are the mass, the angular momentum and their conjugate momenta, which we derive. The Wheeler-DeWitt equation is trivial and describes time independent systems with wave functions described only by the total mass and total angular momentum.

gr-qc↗

arXiv2016

Quantum dust collapse in 2+1 dimensions

In this paper we will examine the consequence of a canonical theory of quantum dust collapse in 2+1 dimensions. The solution of the WDW equation describing the collapse indicates that collapsing shells outside the apparent horizon are accompanied by outgoing shells within the apparent horizon during their collapse phase and stop collapsing once they reach the apparent horizon. Taking this picture of quantum collapse seriously, we determine a static solution with energy density corresponding to a dust ball whose collapse has terminated at the apparent horizon. We show that the boundary radius of the ball is larger than the BTZ radius confirming that no event horizon is formed. The ball is sustained by radial pressure which we determine and which we attribute to the Unruh radiation within it.

gr-qc↗

arXiv2007

To study the effects of degradation of phonon distribution on the high frequency response in nano structures

Under hot electron condition, the hot carriers phonon excited by ultra-short pulses in polar semiconductors initially loose energy rapidly by emitting longitudinal optic phonons via dominant Frolic coupling. Thus, energy supplied to the carriers by high electric fields goes into phonon generation. As the phonon life time is long enough, phonon distribution is disturbed and a non equilibrium population of LO phonons or hot phonons are produced, leading to their re-absorption by the carriers. In the present work the high frequency performance of GaN nanostructures is studied in the framework of heated drifted Fermi-Dirac distribution function incorporating the relevant scattering mechanisms and the influence of non-equilibrium LO phonons. It is observed that degradation of phonon distribution enhances significantly 3-dB cut off frequency thereby makes the high frequency response flatter reflecting that high frequency response is better if effects of non-equilibrium phonon distributions are included in the calculations.

cond-mat.mtrl-sci↗