B M Birla Science Centre

The Mössbauer rotor effect recently gained a renewed interest due to the discovery and explanation of an additional effect of clock synchronization which has been missed for about 50 years, i.e. starting from a famous book of Pauli, till some more recent experimental analyses. The theoretical explanation of such an additional effect is due to some recent papers in the general relativistic framework. Here, we show that the additional effect of clock synchronization can be calculated in another way via the third postulate of relativity.

Abstract In 2014, in a famous paper Hawking strongly criticized the firewall paradox by claiming that it violates the equivalence principle and breaks the CPT invariance of quantum gravity. He proposed that the final result of the gravitational collapse should not be an event horizon, but an apparent horizon instead. On the other hand, Hawking did not give a mechanism for how this could work. In the same year, Vaz endorsed Hawking's proposal in a quantum gravitational model of dust collapse by winning the Second Prize in the 2014 Gravity Research Foundation Essay Competition. He indeed showed that continued collapse to a singularity can only be obtained if one combines two independent and entire solutions of the Wheeler‐DeWitt equation. Vaz's interpretation of the paradox was in terms of simply forbidding such a combination. This leads naturally to matter condensing on the apparent horizon during quantum collapse. In that way, an entirely new framework for black holes (BHs) has emerged. The approach of Vaz was also consistent with Einstein's idea in 1939 of the localization of the collapsing particles within a thin spherical shell. In this work we derive the BH mass and energy spectra via a Schrodinger‐like approach, by further supporting Vaz's conclusions that instead of a spacetime singularity covered by an event horizon, the final result of the gravitational collapse is an essentially quantum object, an extremely compact “dark star”. This “gravitational atom” is held up not by any degeneracy pressure but by quantum gravity in the same way that ordinary atoms are sustained by quantum mechanics. Finally, by evoking the generalized uncertainty principle, the maximum value of the density of Vaz's shell will be estimated.

We apply the Lambert $$W$$ function in the context of complex energy values in statistical systems of fermions and bosons. We derive the condition for the transformation connecting fermions and bosons. We discuss the physical significance of these results and investigate the conditions under which bosonization effects take place. The fermion and boson statistical and structural distributions discussed in this work suggest the possibility of their extensions to generalized Planck distributions.

In this work, we study static spherically symmetric solutions representing wormhole configurations in Poincarè gauge theory ( PGT ). The gravitational sector of the Lagrangian is chosen as a subclass of PGT Lagrangians for which the spin-[Formula: see text] is the only propagating torsion mode. The spacetime torsion in PGT has a dynamical nature even in the absence of intrinsic angular momentum (spin) of matter, hence torsion can play a principal role in the case of usual spin-less gravitating systems. We therefore consider a spin-less matter distribution with an anisotropic energy–momentum tensor ( EMT ) as the supporting source for wormhole structure to obtain a class of zero tidal force wormhole solutions. It is seen that the matter distribution obeys the physical reasonability conditions, i.e. the weak ( WEC ) and null ( NEC ) energy conditions either at the throat and throughout the spacetime. We further consider varying equations of state in radial and tangential directions via definitions [Formula: see text] and [Formula: see text] and investigate the behavior of state parameters at the throat of wormhole. We observe that our solutions allow for wormhole configurations without the need of exotic matter. Observational features of the wormhole solutions are also discussed utilizing gravitational lensing effects. It is found that the light deflection angle diverges at the throat (which indeed, effectively acts as a photon sphere) and can get zero and negative values depending on the model parameters.

The Riemann Hypothesis states that the Riemann zeta function ζ(z) admits a set of ‘non-trivial’ zeros that are complex numbers supposed to have real part 1/2. Their distribution on the complex plane is thought to be the key to determine the number of prime numbers before a given number. Hilbert and Pólya suggested that the Riemann Hypothesis could be solved through the mathematical tools of physics, finding a suitable Hermitian or unitary operator that describe classical or quantum systems, whose eigenvalues distribute like the zeros of ζ(z). A different approach is that of finding a correspondence between the distribution of the ζ(z) zeros and the poles of the scattering matrix S of a physical system. Our contribution is articulated in two parts: in the first we apply the infinite-components Majorana equation in a Rindler spacetime and compare the results with those obtained with a Dirac particle following the Hilbert-Pólya approach showing that the Majorana solution has a behavior similar to that of massless Dirac particles and finding a relationship between the zeros of zeta end the energy states. Then, we focus on the S-matrix approach describing the bosonic open string scattering for tachyonic states with the Majorana equation. Here we find that, thanks to the relationship between the angular momentum and energy/mass eigenvalues of the Majorana solution, one can explain the still unclear point for which the poles and zeros of the S-matrix of an ideal system that can satisfy the Riemann Hypothesis, exist always in pairs and are related via complex conjugation. As claimed in the literature, if this occurs and the claim is correct, then the Riemann Hypothesis could be in principle satisfied, tracing a route to a proof.

A new experiment for gravitational waves (GWs) detection is proposed. It is shown that the effect of GWs on sound waves (SWs) in a fluid is that GWs vary the pressure of the fluid as they pass through it. This variation can be found by analysing the gauge of the local observer. It is shown that one can, in principle, detect GWs through the proposed new experiment. The variation of the pressure of the fluid, which represents detected signals, is indeed much higher than the corresponding values of GW amplitudes. The examples of rotating neutron stars (NSs) and relic GWs are discussed. Remarkably, a comparison of the proposed new method with a previous paper of Singh et al. (New J. Phys. 19, 073023 (2017). doi: 10.1088/1367-2630/aa78cb ) on a similar approach shows a possible improvement of the sensitivity concerning the potential detection of GWs. It must be emphasized that this proposed procedure may be difficult in practical experiments because of the presence of different types of noise. For this reason, a section of the paper is dedicated to the discussion of such noise. On the other hand, this paper must be considered as pioneering the new proposed approach. Thus, we hope that in future more precise studies of the noise that concerns the proposed new experiment will be done.

The non-zero minimal length arises in various theories of gravity, leading to the so-called generalized uncertainty principle (GUP). In this short paper we analyze the GUP effects on neutron interferometry, showing that the obtained phase shifts depend on the mass and velocity of the particle. New upper bounds on the dimensionless GUP parameter have been found that are in agreement with the literature.

It was pointed out by Ezra Newman in the sixties that an imaginary shift of the coordinate in purely classical equations leads to the purely quantum mechanical gyromagnetic ratio g = 2. Newman puzzled about it for decades and finally could not explain this enigmatic finding. The author, Dr. B G Sidharth, Director, B M Birla Science Centre, Hyderabad, has been working on this for a few decades and has concluded the following: 1. The explanation lies at very small scales where the square of the Compton scale is retained and 2. When a complex coordinate is generalized to three dimensions, as Sachs had pointed out we end up with a four dimensional space, which moreover has a Minkowski invariant thrown in. On a further analysis the author noted that in this quaternionic description the spacetime is rather different to the simple Minkowski spacetime. To put it pictorially the former resembles the curly spiral binding while the latter is more like the smooth paper. The author also concluded that this was the reason why despite a century of efforts Einstein’s gravitation could not be reconciled with particle physics. Moving on we consider the second order representation of the quaternions in terms of the 2 × 2 Pauli matrices. This time the line element will be given by σ(i)xi. We get again an invariant but unlike in the 4 × 4 matrix consideration, this time there is no invariance under the reflection symmetry. We consider the different situations like neutrinos, noncommutative geometry and two dimensional surfaces like graphene where this latter case applies.

Abstract The study of processes and change in systems is a requirement for Theoretical Physics after the development of complexity and emergence theories. This matter is far beyond the ideal models—centered on predictability—that Mathematical Physics usually deals with. The strongly interdisciplinary and systemic issue of a Theories of Change implies a careful reconsidering of the essential features of the relationships between the observer/model-builder and the system under consideration. We delineate here such relationship as the meta-theoretical step wherein it is possible to give the first and partial collocation to the wide class of not ideal models, and to evaluate the effective forecasting possibilities of Big Data.KeywordsComplexityEmergenceIdeal and not-ideal modelsPredictabilityChangeBig Data

We propose a new thought experiment, based on present-day Quantum Information Technologies, to measure quantum gravitational effects through the Bose-Marletto-Vedral (BMV) effect [1–4] by revealing the gravitational t3 phase term, its expected relationships with low-energy quantum gravity phenomena and test the equivalence principle of general relativity. The technique here proposed promise to reveal gravitational field fluctuations from the analysis of the stochastic noise associated to an ideal output of a measurement process of a quantum system. To improve the sensitivity we propose to cumulate the effects of the gravitational field fluctuations in time on the outputs of a series of independent measurements acted on entangled states of particles, like in the building of a quantum cryptographic key, and extract from the associated time series the effect of the expected gravitational field fluctuations. In fact, an ideal quantum cryptographic key, built with the sharing of maximally entangled states of particles, is represented by a random sequence of uncorrelated symbols mathematically described by a perfect white noise, a stochastic process with zero mean and without correlation between its values taken at different times. Gravitational field perturbations, including quantum gravity fluctuations and gravitational waves, introduce additional phase terms that decohere the entangled pairs used to build the quantum cryptographic key, with the result of coloring the white noise [5,6]. We find that this setup, built with massive mesoscopic particles, can potentially reveal the t3 gravitational phase term and thus, the BMV effect.