Statistical properties of eigenstate amplitudes in complex quantum systems

We study the eigenstates of quantum systems with large Hilbert spaces, via their distribution of wavefunction amplitudes in a real-space basis. For single-particle 'quantum billiards', these real-space amplitudes are known to have Gaussian distribution for chaotic systems. In this work, we formulate and address the corresponding question for many-body lattice quantum systems. For integrable many-body systems, we examine the deviation from Gaussianity and provide evidence that the distribution generically tends toward power-law behavior in the limit of large sizes. We relate the deviation from Gaussianity to the entanglement content of many-body eigenstates. For integrable billiards, we find several cases where the distribution has power-law tails.Comment: revised version, with appendices; 15 pages, 10 figure

The gravitational analogue to the hydrogen atom (A summer study at the borders of quantum mechanics and general relativity)

This article reports on a student summer project performed in 2006 at the University of Frankfurt. It is addressed to undergraduate students familiar with the basic principles of relativistic quantum mechanics and general relativity. The aim of the project was to study the Dirac equation in curved space time. To obtain the general relativistic Dirac equation we use the formulation of gravity as a gauge theory in the first part. After these general considerations we restrict the further discussion to the special case of the Schwarzschild metric. This setting corresponds to the hydrogen atom, with the electromagnetic field replaced by gravity. Although there is a singularity at the event horizon it turns out that a regular solution of the time independent Dirac equation exists. Finally the Dirac equation is solved numerically using suitable boundary conditions.Comment: 19 pages, 3 figure

A reduced model for shock and detonation waves. II. The reactive case

We present a mesoscopic model for reactive shock waves, which extends a previous model proposed in [G. Stoltz, Europhys. Lett. 76 (2006), 849]. A complex molecule (or a group of molecules) is replaced by a single mesoparticle, evolving according to some Dissipative Particle Dynamics. Chemical reactions can be handled in a mean way by considering an additional variable per particle describing a rate of reaction. The evolution of this rate is governed by the kinetics of a reversible exothermic reaction. Numerical results give profiles in qualitative agreement with all-atom studies

Energy Security of China, India, the E.U. and the U.S. under Long-term Scenarios: Results from Six IAMs

This paper assesses energy security in three long-term energy scenarios (a business as usual development, a projection of Copenhagen commitments, and a 450 ppm stabilization scenario) as modeled in six integrated assessment models: GCAM, IMAGE, MESSAGE, ReMIND, TIAM-ECN and WITCH. We systematically evaluate potential long-term vulnerabilities of vital energy systems of four major economies: China, the European Union, India and the U.S., as expressed by several characteristics of energy trade, resource extraction, and diversity of energy options. Our results show that climate policies are likely to lead to significantly lower global energy trade and reduce energy imports of major economies, decrease the rate of resource depletion, and increase the diversity of energy options, particularly in the especially vulnerable transportation sector. China, India and the E.U. will derive particularly strong benefits from climate policies, whereas the U.S. may forego some opportunities to export fossil fuels in the second half of the century

Posttranscriptional regulation of PARG mRNA by HuR facilitates DNA repair and resistance to PARP inhibitors

The majority of pancreatic ductal adenocarcinomas (PDAC) rely on the mRNA stability factor HuR (ELAV-L1) to drive cancer growth and progression. Here, we show that CRISPR-Cas9–mediated silencing of the HuR locus increases the relative sensitivity of PDAC cells to PARP inhibitors (PARPi). PDAC cells treated with PARPi stimulated translocation of HuR from the nucleus to the cytoplasm, specifically promoting stabilization of a new target, poly (ADP-ribose) glycohydrolase (PARG) mRNA, by binding a unique sequence embedded in its 30 untranslated region. HuR-dependent upregulation of PARG expression facilitated DNA repair via hydrolysis of polyADP-ribose on related repair proteins. Accordingly, strategies to inhibit HuR directly promoted DNA damage accumulation, inefficient PAR removal, and persistent PARP-1 residency on chromatin (PARP-1 trapping). Immunoprecipitation assays demonstrated that the PARP-1 protein binds and posttranslationally modifies HuR in PARPi-treated PDAC cells. In a mouse xenograft model of human PDAC, PARPi monotherapy combined with targeted silencing of HuR significantly reduced tumor growth compared with PARPi therapy alone. Our results highlight the HuR–PARG axis as an opportunity to enhance PARPi-based therapies. ©2017 AACR

Robin conditions on the Euclidean ball

Techniques are presented for calculating directly the scalar functional determinant on the Euclidean d-ball. General formulae are given for Dirichlet and Robin boundary conditions. The method involves a large mass asymptotic limit which is carried out in detail for d=2 and d=4 incidentally producing some specific summations and identities. Extensive use is made of the Watson-Kober summation formula.Comment: 36p,JyTex, misprints corrected and a section on the massive case adde

Maternal Neural Responses to Infant Cries and Faces: Relationships with Substance Use

Substance abuse in pregnant and recently post-partum women is a major public health concern because of effects on the infant and on the ability of the adult to care for the infant. In addition to the negative health effects of teratogenic substances on fetal development, substance use can contribute to difficulties associated with the social and behavioral aspects of parenting. Neural circuits associated with parenting behavior overlap with circuits involved in addiction (e.g., frontal, striatal, and limbic systems) and thus may be co-opted for the craving/reward cycle associated with substance use and abuse and be less available for parenting. The current study investigates the degree to which neural circuits associated with parenting are disrupted in mothers who are substance-using. Specifically, we used functional magnetic resonance imaging to examine the neural response to emotional infant cues (faces and cries) in substance-using compared to non-using mothers. In response to both faces (of varying emotional valence) and cries (of varying distress levels), substance-using mothers evidenced reduced neural activation in regions that have been previously implicated in reward and motivation as well as regions involved in cognitive control. Specifically, in response to faces, substance users showed reduced activation in prefrontal regions, including the dorsolateral and ventromedial prefrontal cortices, as well as visual processing (occipital lobes) and limbic regions (parahippocampus and amygdala). Similarly, in response to infant cries, substance-using mothers showed reduced activation relative to non-using mothers in prefrontal regions, auditory sensory processing regions, insula and limbic regions (parahippocampus and amygdala). These findings suggest that infant stimuli may be less salient for substance-using mothers, and such reduced saliency may impair developing infant-caregiver attachment and the ability of mothers to respond appropriately to their infants