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Adler Stephen L. | Adler S. S. | Adler V. E. | Adler Mark | Adler Robert J. | Adler Jeffrey D. | Adler Isolde | Adler Joan | Adler M. | Adler Ronald J.

Stephen J. B. | Stephen Tamon | Stephen J. | Stephen Julia M. | Stephen David T. | Stephen Sudeep | Stephen John B. | Stephen Gregory M. | Stephen Matthew | Stephen Reuben George

L | L Navaneet K | L Smitha M. | L Srikanth P | L Aashiha Priyadarshni. | L Alex F Estupiñán | L Alex F. Estupiñán | L Altamirano-Dévora | L Arun S | L Berdinskiy V.

17 Aug 2020
astro-ph.CO gr-qc
arxiv.org/abs/2008.07598

We extend our previous analysis of a model for "dark energy" based on a Weyl scaling invariant dark energy action. We reexpress all prior results in terms of proper time, and derive a compact formula for the squared effective Hubble parameter in the model. This formula involves effective dark energy and matter densities that differ from their expressions in the standard $\Lambda CDM$ cosmology, and are illustrated by sample numerical results. We also give new analytic results for the function $ \Phi(x)$ governing evolution of deviations from the standard cosmology, and discuss their implications.

24 Nov 2019
hep-ph
arxiv.org/abs/1911.10607

In earlier work we analyzed an abelianized model in which a gauged Rarita-Schwinger spin-$\frac{3}{2}$ field is directly coupled to a spin-$\frac{1}{2}$ field. Here we extend this analysis to the gauged $SU(8)$ model for which the abelianized model was a simplified substitute. We calculate the gauge anomaly, show that anomaly cancellation requires adding an additional left chiral representation $\overline{8}$ spin-$\frac{1}{2}$ fermion to the original fermion complement of the $SU(8)$ model, and give options for restoring boson-fermion balance. We conclude with a summary of attractive features of the reformulated $SU(8)$ model, including a possible connection to the $E_8$ root lattice.

09 Oct 2019
hep-th
arxiv.org/abs/1910.04089

I begin with an anecdote, and then discuss my recent work on anomalies in spin-$\frac{3}{2}$ theories.

25 Sep 2019
quant-ph
arxiv.org/abs/1909.11301

The CSL model predicts a progressive breakdown of the quantum superposition principle, with a noise randomly driving the state of the system towards a localized one, thus accounting for the emergence of a classical world within a quantum framework. In the original model the noise is supposed to be white, but since white noises do not exist in nature, it becomes relevant to identify some of its spectral properties. Experimental data set an upper bound on its frequencies, while in this paper we bound it from below. We do so in two ways: by considering a 'minimal' measurement setup, requiring that the collapse is completed within the measurement time; and in a measurement modeling-independent way, by requiring that the fluctuations average to zero before the measurement time.

26 Jul 2019
quant-ph
arxiv.org/abs/1907.11598

For a solid lattice, we rederive the CSL noise total energy gain of a test mass starting from a Lindblad formulation, and from a similar starting point rederive the geometry factor governing center of mass energy gain. We then suggest that the geometry factor can be used as a way to distinguish between low temperature cantilever motion saturation arising from CSL noise, and saturation arising from thermal leakage.

20 May 2019
astro-ph.CO gr-qc hep-ph hep-th
arxiv.org/abs/1905.08228

In earlier papers we showed that a frame dependent effective action motivated by the postulates of three-space general coordinate invariance and Weyl scaling invariance exactly mimics a cosmological constant in Friedmann-Robertson-Walker (FRW) spacetimes, but alters the linearized equations governing scalar perturbations around a spatially flat FRW background metric. Here we analyze the implications of a frame dependent dark energy for the spacetime cosmological metric within both a perturbative and a non-perturbative framework. Both methods of calculation give a one-parameter family of cosmologies which are in close correspondence to one another, and which contain the standard FRW cosmology as a special case. We discuss the application of this family of cosmologies to the standard cosmological distance measures and to the effective Hubble parameter, with special attention to the current tension between determinations of the Hubble constant at late time, and the Hubble value obtained through the cosmic microwave background (CMB) angular fluctuation analysis.

14 Mar 2019
hep-th
arxiv.org/abs/1903.06189

We recalculate the chiral anomaly in the Abelian gauge model in which a spin-$\frac{1}{2}$ field is directly coupled to a Rarita-Schwinger spin-$\frac{3}{2}$ field, using the extended theory in which there is an exact fermionic gauge invariance. Since the standard gauge fixing and ghost analysis applies to this theory, the ghost contribution to the chiral anomaly is $-1$ times the standard chiral anomaly for spin-$\frac{1}{2}$. Calculation of the fermion loop Feynman diagrams contributing to the coupled model anomaly gives a result of $6$ times the standard anomaly, so the total anomaly is $5$ times the standard anomaly. This agrees with the result obtained from the unextended model taking the ghost contribution there as $0$, corresponding to a non-propagating ghost arising from exponentiating the second class constraint determinant, together with the fermion loop anomaly contribution in the unextended model of $5$ times the standard anomaly.

30 Jan 2019
quant-ph astro-ph.HE gr-qc
arxiv.org/abs/1901.10963

Collapse models describe phenomenologically the quantum-to-classical transition by adding suitable nonlinear and stochastic terms to the Schroedinger equation, thus (slightly) modifying the dynamics of quantum systems. Experimental bounds on the collapse parameters have been derived from various experiments involving a plethora of different systems, from single atoms to gravitational wave detectors. Here, we give a comprehensive treatment of the Continuous Spontaneous Localization (CSL) model, the most studied among collapse models, for Fermi liquids. We consider both the white and non-white noise case. Application to various astrophysical sources is presented.

18 Jan 2019
hep-ph
arxiv.org/abs/1901.06445

I review the role that soft pion theorems, current algebras, sum rules, and anomalies played in the foundation of the standard model.

30 Jul 2018
quant-ph
arxiv.org/abs/1807.11450

We review the argument that latent image formation is a measurement in which the state vector collapses, requiring an enhanced noise parameter in objective reduction models. Tentative observation of a residual noise at this level, plus several experimental bounds, imply that the noise must be colored (i.e., non-white), and hence frame dependent and non-relativistic. Thus a relativistic objective reduction model, even if achievable in principle, would be incompatible with experiment, the best one can do is the non-relativistic CSL model. This negative conclusion has a positive aspect, in that the non-relativistic CSL reduction model evades the argument leading to the Conway--Kochen "Free Will Theorem".