Bounds on gravitational parity violation using a rotating torsion pendulum with chiral masses

In this letter we employ recent results on gravitationally induced parity violation with a rotating torsion pendulum whose test bodies are quartz enantiomers (Zhu et al. in Phys Rev Lett 121:261101, 2018) in order to estimate, using a simple model, Hari Dass’s α2 constant which parametrizes the strength of parity violation in the gravitational interaction. The result here obtained, α2∼1017, is in agreement with estimations based on high resolution experiments performed using chiral molecules, showing that the Hari-Dass’s framework for spin-dependent gravity, together with our simple model, are versatile enough in order to be applied to the analysis of other experimental results involving spin-dependent gravitational effects. Interestingly, it can also be used to constrain indirectly parity-violating effects in macroscopic samples of quartz crystals due to electron–nucleon interactions.P. B. is funded by the Beatriz Galindo contract Ministerio de Educación y Formación Profesional BEAGAL 18/00207, Spain

Communication: theoretical exploration of Au+H2, D2, and HD reactive collisions

The following article appeared in Journal of Chemical Physic 135.9 (2011): 091102 and may be found at http://scitation.aip.org/content/aip/journal/jcp/135/9/10.1063/1.3635772A quasi-classical study of the endoergic Au(1S)+ H2(X1Σg+) → AuHAuH+(2Σ+)+H(2S) reaction, and isotopic variants, is performed to compare with recent experimental results [F. Li, C. S. Hinton, M. Citir, F. Liu, and P. B. Armentrout, J. Chem. Phys. 134, 024310 (2011)]. For this purpose, a new global potential energy surface has been developed based on multi-reference configuration interaction ab initio calculations. The quasi-classical trajectory results show a very good agreement with the experiments, showing the same trends for the different isotopic variants of the hydrogen molecule. It is also found that the total dissociation into three fragments, Au+H+H, is the dominant reaction channel for energies above the H2 dissociation energy. This results from a well in the entrance channel of the potential energy surface, which enhances the probability of H-Au-H insertionA.D.-U. acknowledges a JAE fellowship supported by CSIC. This work is supported by Comunidad Autónoma de Madrid, Grant No. S2009/MAT/1467, and by Ministerio de Ciencia e Innovación, Grant Nos. CSD2009-00038 and FIS2010-18132. The calculations have been performed at CESGA and IFF computing centers. P.B.A. thanks the National Science Foundation for suppor

Electron transport signature of H2 dissociation on atomic gold wires

Nonequilibrium Green’s functions calculations based on density functional theory show a direct link between the initial stages of H2 dissociation on a gold atomic wire and the electronic current supported by the gold wire. The simulations reveal that for biases below the stability threshold of the wire, the minimum-energy path for H2 dissociation is not affected. However, the electronic current presents a dramatic drop when the molecule initiates its dissociation. This current drop is traced back to quantum interference between electron paths when the molecule starts interacting with the gold wireThis work has been supported by Comunidad Autónoma de Madrid (CAM) under Grant No. S-2009/MAT/1467, by the Ministerio de Ciencia e Innovación under Grant No. FIS2011-29596-C02, and by the European-Union Integrated Project AtMol (http://www.atmol.eu). We would like to thank as well the CESGA computing center for the computing time under the ICTS grant

Homochirality: A Perspective from Fundamental Physics

In this brief review, possible mechanisms which could lead to complete biological homochirality are discussed from the viewpoint of fundamental physics. In particular, the role played by electroweak parity violation, including neutrino-induced homochirality, and contributions from the gravitational interaction, will be emphasized

A Study of the pressure-induced reversible amorphization of Xe containing-LTA zeolites by energy minimization technique

A previous computational study on dehydrated LTA zeolites [J. Gulín-González, G.B. Suffritti, Micropor. Mesopor. Mater. 69 (2004) 127] suggested the reversible amorphization of calcined LTA samples at pressures below 6 GPa, in agreement with the experimental results. However, the effect of guest molecules on the amorphization process was not evaluated in that study. In this paper, the potential reversible amorphization of Xe containing-LTA samples under high external pressures is studied via energy minimization calculations. The results of the simulations confirmed the pressure-induced amorphization of LTA zeolites at pressures about 2–4 GPa for all the studied samples. Besides, the simulations stressed the importance of the structural topology, particularly of D4R secondary units, for the recovering of the crystalline order. According to our calculations the exchangeable cations (Na+ and Li+) play a crucial role in the process of amorphization. Our results suggest that the reversible amorphization is essentially independent on the presence of Xe molecules in the range of the pressures studied (P ≤ 6 GPa)