arXiv subjects

Abhishek Kumar Jha

Publications and source records attributed to Abhishek Kumar Jha.

10 recordsLinked to original sources

arXiv2026

Lepton asymmetry leading to baryogenesis by primordial black holes

Baryogenesis remains an unresolved problem in cosmology, with existing mechanisms facing significant caveats. We show that the effects of primordial black holes (PBHs) on neutrinos produce the lepton asymmetry $\sim 10^{-10}$ which subsequently produces the baryon asymmetry. We consider the Dirac Lagrangian in curved spacetime in local coordinates exhibiting Hermitian pseudo-vector and non-Hermitian vector terms. These terms lead to energy splitting between weakly interacting neutrinos and antineutrinos, resulting in their unequal number densities and hence a lepton asymmetry. While the non-Hermitian effect leads to a non-conserved total probability of neutrinos, the leptogenesis due to gravitational effects of a PBH could be significant until the nucleosynthesis era. This in turn produces baryon asymmetry from the symmetry of lepton and baryon numbers via the sphaleron process in the electro-weak era. We show that in the most conservative scenario, the PBHs of mass $\sim 10^{12}$ g and spin $\sim 0.01$ produce the observed baryogenesis at temperature 130 GeV, when such PBHs are available abundantly. However, massive PBHs also could produce the observed asymmetry, assuming the non/anti-Hermitian vector couplings for neutrino and anti-neutrino get canceled from the Lagrangian, leading the system to be Hermitian.

hep-ph↗

arXiv2026

Quantum speed limit time for bipartite entanglement in neutrino oscillations in matter with non-standard interactions

In the three-flavor neutrino oscillation framework, we investigate the transition probabilities of an initial muon neutrino flavor state in the presence of non-standard interactions (NSIs) characterized by complex off-diagonal ($|ε_{αβ}|e^{iϕ_{αβ}}$) and diagonal parameters ($|ε_{αα}-ε_{ββ}|$), including a CP-violating phase and a constant matter potential, under both normal (NO) and inverted mass ordering (IO) scenarios. Within these scenarios and through the lens of mode entanglement, bipartite entanglement measures such as entanglement entropy and capacity of entanglement are quantified in terms of the transition probabilities, which can be measured in neutrino oscillation experiments. Using these two bipartite entanglement measures, we further explore the quantum speed limit (QSL) time, which describes how rapidly bipartite entanglement evolves during neutrino oscillations. We illustrate our results using the baseline lengths and energies corresponding to ongoing long-baseline accelerator neutrino experiments, such as T2K, NO$ν$A, and the upcoming DUNE experiment. In the presence of a CP-violating phase and a constant matter potential, both with and without NSI effects, we compare the QSL time behavior for bipartite entanglement in neutrino oscillations for NO and IO. The most pronounced discrepancies in the QSL time for bipartite entanglement arise from the off-diagonal NSI parameter $ε_{μτ}$ across both the NO and IO scenarios. We emphasize that among all the experiments considered, NO$ν$A and DUNE exhibit a rapid suppression of bipartite entanglement in neutrino oscillations in the standard oscillation scenario with NO at the end of their baseline lengths for the corresponding best-fit value of CP-violating phase. Our results hint at a possible imprint of new physics in neutrino oscillations.

hep-ph↗

arXiv2025

Quantum spread complexity as a probe of NSI, $CP$ Violation, and mass ordering in neutrino oscillations in matter

Quantum spread complexity characterizes how a quantum state evolves and becomes distributed over the Hilbert space under unitary dynamics. In this work, we employ a cost function as a quantitative measure of spread complexity. We investigate this cost function within the framework of three-flavor neutrino oscillations in vacuum and matter, incorporating the $CP$-violation phase and Non-Standard Interaction (NSI) effects, under both normal and inverted mass ordering scenarios. The cost function is evaluated for each scenario and analyzed with the corresponding neutrino transition probabilities for both initial muon neutrino and muon antineutrino flavor states. The results are presented using the energy where the first oscillation is maximum and baseline lengths of ongoing long-baseline accelerator neutrino experiments, including T2K and NOvA, as well as upcoming experiments such as DUNE and P2O. Our findings indicate that the difference in the cost function between normal and inverted mass orderings during neutrino propagation in matter is sensitive to these experiments, with the appropriate choice of NSI parameters and the best-fit $CP$-violation phase values.

hep-ph↗

arXiv2025

Probing the quantum speed limit and entanglement in flavor oscillations of neutrino-antineutrino system in curved spacetime

We consider a spinning primordial black hole (PBH) described by the Kerr metric in Kerr-Schild polar coordinates. We derive an analytical expression for the four-vector gravitational potential in the underlying Hermitian Dirac Hamiltonian using these coordinates. This gravitational potential introduces an axial vector term in the Dirac equation in curved spacetime. We find that the magnitudes of the temporal and spatial components of the four-vector gravitational potential are significantly affected by the angle of the position vector of the spinor with respect to the spin axis of the PBH, its radial distance from the PBH, and the strength of the specific angular momentum of the PBH. These potentials modify the effective mass matrix of the neutrino-antineutrino system and significantly affect the transition probabilities during the flavor oscillation of the neutrino-antineutrino system. We then use the transition probability to investigate the quantum speed limit time bound ratio for the two-flavor oscillation of the neutrino-antineutrino system in curved spacetime. This helps us estimate how quickly the initial neutrino flavor state evolves over time under the influence of the gravitational field. Finally, we discuss quantum correlations such as entanglement entropy during the two-flavor oscillation of the neutrino-antineutrino system near a spinning PBH.

gr-qc↗

arXiv2025

Probing $CP$ violation and mass ordering in neutrino oscillations in matter through quantum speed limits

The quantum speed limits (QSLs) set fundamental lower bounds on the time required for a quantum system to evolve from a given initial state to a final state. In this work, we investigate $CP$ violation and the mass ordering problem of neutrino oscillations in matter using the QSL time as a key analytical tool. We examine the QSL time for the unitary evolution of two- and three-flavor neutrino states, both in vacuum and in the presence of matter. Two-flavor neutrino oscillations are used as a precursor to their three-flavor counterparts. We further compute the QSL time for neutrino state evolution and entanglement in terms of neutrino survival and oscillation probabilities, which are experimentally measurable quantities in neutrino experiments. A difference in the QSL time between the normal and inverted mass ordering scenarios, for neutrino state evolution as well as for entanglement, under the effect of a $CP$ violation phase is observed. Our results are illustrated using the length scales and energies of ongoing long-baseline accelerator neutrino experiments such as T2K, NOvA, and the upcoming DUNE experiment. Notably, three-flavor neutrino oscillations in constant matter density exhibit faster state evolution across all these neutrino experiments in the normal mass ordering scenario. Additionally, we observe fast entanglement suppression in DUNE assuming a normal mass ordering.

hep-ph↗

arXiv2024

Gravitational Influence on the Quantum Speed Limit in Flavor Oscillations of Neutrino-Antineutrino System

We investigate the quantum speed limit (QSL) during the time evolution of neutrino-antineutrino system under the influence of the gravitational field of a spinning primordial black hole (PBH). We derive an analytical expression for the four-vector gravitational potential in the underlying Hermitian Dirac Hamiltonian using the Boyer-Lindquist (BL) coordinates. This gravitational potential leads to an axial vector term in the Dirac equation in curved spacetime, contributing to the effective mass matrix of the neutrino-antineutrino systems. Our findings indicate that the gravitational field, expressed in BL coordinates, significantly influences the transition probabilities in two-flavor oscillations of the neutrino-antineutrino system. We then apply the expression for transition probabilities between states to analyze the Bures angle, which quantifies the closeness between the initial and final states of the time-evolved flavor state. We use this concept to probe the QSL for the time evolution of the initial flavor neutrino state.

gr-qc↗

arXiv2024

Influence of gravity on the quantum speed limit in neutrino oscillations

The quantum speed limits (QSLs) determine the minimal amount of time required for a quantum system to evolve from an initial to a final state. We investigate QSLs for the unitary evolution of the neutrino-antineutrino system in the presence of a gravitational field. It is known that the transition probabilities between neutrino and antineutrino in the framework of one and two flavors depend on the strength of the gravitational field. The behavior of the QSL time in the two-flavor system indicates fast flavor transitions as the gravitational field strength increases. Subsequently, we observe quick suppression of entanglement by exploring the speed limit for entanglement entropy of two-flavor oscillations in the neutrino-antineutrino system in the proximity of a spinning primordial black hole.

gr-qc↗

arXiv2024

Neutrinos as qubits and qutrits

We map neutrinos to qubit and qutrit states of quantum information theory by constructing the Poincaré sphere using SU(2) Pauli matrices and SU(3) Gell-Mann matrices, respectively. The construction of the Poincaré sphere in the two-qubit system enables us to construct the Bloch matrix, which yields valuable symmetries in the Bloch vector space of two neutrino systems. By identifying neutrinos with qutrits, we calculate the measures of qutrit entanglement for neutrinos. We use SU(3) Gell-Mann matrices tensor products to construct the Poincaré sphere of two qutrits neutrino systems. The comparison between the entanglement measures of bipartite qubits and bipartite qutrits in the two neutrino system are shown. The result warrants a study of two qutrits entanglement in the three neutrino system.

hep-ph↗

arXiv2020

Quantum simulation of oscillating neutrinos

Two and three flavor oscillating neutrinos are shown to exhibit the properties bipartite and tripartite quantum entanglement. The two and three flavor neutrinos are mapped to qubit states used in quantum information theory. Such quantum bits of the neutrino state can be encoded on a IBMQ computer using quantum computing as a tool. We show the implementation of entanglement in the two neutrino system on the IBM quantum processor.

hep-ph↗

arXiv2020

Tri-Partite entanglement in Neutrino Oscillations

We investigate and quantify various measures of bipartite and tripartite entanglement in the context of two and three flavor neutrino oscillations. The bipartite entanglement is analogous to the entanglement swapping resulting from a beam splitter in quantum optics. For the three neutrino systems various measures of tripartite entanglement are explored. The significant result is that a monogamy inequality in terms of negativity leads to a residual entanglement, implying true tripartite entanglement in the three neutrino system. This leads us to an analogy of the three neutrino state with a generalized class of W-state in quantum optics.

hep-ph↗