Spin excitations in layered antiferromagnetic metals and superconductors

The proximity of antiferromagnetic order in high-temperature superconducting materials is considered a possible clue to the electronic excitations which form superconducting pairs. Here we study the transverse and longitudinal spin excitation spectrum in a one-band model in the pure spin density wave (SDW) state and in the coexistence state of SDW and the superconductivity. We start from a Stoner insulator and study the evolution of the spectrum with doping, including distinct situations with only hole pockets, with only electron pockets and with pockets of both types. In addition to the usual spin-wave modes, in the partially gapped cases we find significant weight of low-energy particle-hole excitations. We discuss the implications of our findings for neutron scattering experiments and for theories of Cooper-pairing in the metallic SDW state.Comment: (14 pages, 6 figures

How Would You Like to Die? Glossip v. Gross Deals Blow to Abolitionists

After capital punishment opponents’ pressure on drug suppliers reduced the lethal injection drug supply, Oklahoma began using midazolam, resulting in botched executions. Condemned inmates sought to stop use of this lethal injection protocol. In Glossip v. Gross, the U.S. Supreme Court found inmates failed to establish such protocols entail a substantial risk of severe pain compared to available alternatives, undermining the supply side attack strategy and leaving inmates facing the possibility of an unnecessarily painful execution. This article places the Glossip decision within the context of method of execution jurisprudence and discusses implications for the ongoing battle over capital punishment

Get Out of My Driveway! Collins v. Virginia Protects Curtilage from Being Trampled by the Automobile Exception

In Collins v. Virginia (2018), the U.S. Supreme Court held that the automobile exception cannot justify a warrantless search of an automobile parked in a home’s curtilage because the automobile exception pertains solely to the search of the automobile, not to the intrusion upon the Fourth Amendment privacy interest in the home’s curtilage. After giving an overview of relevant Fourth Amendment jurisprudence concerning the curtilage doctrine and the automobile exception as well as the history of the exclusionary rule, this article examines the majority, concurring, and dissenting opinions in Collins and discusses the implications of this important decision. Collins preserves the heightened Fourth Amendment protection afforded to the home and its curtilage by refusing to further expand the automobile exception. Collins is also notable for Justice Thomas’s concurrence, which questions the Court’s authority to impose the exclusionary rule upon the states. Given the changing composition of the Court, the Court’s eventual reconsideration of the exclusionary rule’s applicability to the states is a possibility that bears watching

Predictors of Texas Police Chiefs’ Satisfaction with Police-Prosecutor Relationships

Although strain in police-prosecutor relationships may be built into the criminal justice system’s checks and balances, the administration of criminal justice can benefit from the adoption of practices which improve these working relationships. A first step towards the adoption of such practices can be taken by first adding to the knowledge base regarding this understudied topic. Using a survey of a state-wide sample of Texas police chiefs, this exploratory study identifies which aspects of police-prosecutor interaction styles are predictors of police chiefs’ satisfaction with police-prosecutor relationships. Results indicate that perceived level of police input in prosecutors’ plea bargain and charging decisions, perceived directness of felony trial preparation communication method, and perceived frequency of decision-maker interactions predict police chiefs’ satisfaction with police-prosecutor relationships. Policy implications are discussed

Transnational State-sponsored Cyber Economic Espionage: A Legal Quagmire

Transnational state-sponsored cyber economic espionage poses a threat to the economy of developed countries whose industry is largely reliant on the value of information. In the face of rapid technological development facilitating cyber economic espionage from afar on a massive scale, the law has not developed apace to effectively address this problem. Applicable United States domestic laws have been ineffective in addressing the problem due to lack of enforcement jurisdiction, sovereign immunity, and inability to hold the state sponsor accountable. Customary international law principles offer little help in combatting the issue, as countermeasures are typically unavailable since espionage may not be ongoing by the time a victimized state can confidently attribute it to a state and retortions are a relatively weak response. Although existing treaties have not been effective in addressing this problem, a multilateral global treaty specifically addressing transnational state-sponsored cyber economic espionage may be a promising way forward

The Tamm-Dancoff Approximation as the boson limit of the Richardson-Gaudin equations for pairing

A connection is made between the exact eigen states of the BCS Hamiltonian and the predictions made by the Tamm-Dancoff Approximation. This connection is made by means of a parametrised algebra, which gives the exact quasi-spin algebra in one limit of the parameter and the Heisenberg-Weyl algebra in the other. Using this algebra to construct the Bethe Ansatz solution of the BCS Hamiltonian, we obtain parametrised Richardson-Gaudin equations, leading to the secular equation of the Tamm-Dancoff Approximation in the bosonic limit. An example is discussed in depth.Comment: Submitted to the proceedings of the Group28 conference (Newcastle-upon-Tyne, UK). Journal of Physics: Conference Serie

Representations of the Weyl group and Wigner functions for SU(3)

Bases for SU(3) irreps are constructed on a space of three-particle tensor products of two-dimensional harmonic oscillator wave functions. The Weyl group is represented as the symmetric group of permutations of the particle coordinates of these space. Wigner functions for SU(3) are expressed as products of SU(2) Wigner functions and matrix elements of Weyl transformations. The constructions make explicit use of dual reductive pairs which are shown to be particularly relevant to problems in optics and quantum interferometry.Comment: : RevTex file, 11 pages with 2 figure

Genotype-environment associations support a mosaic hybrid zone between two tidal marsh birds

Local environmental features can shape hybrid zone dynamics when hybrids are bounded by ecotones or when patchily distributed habitat types lead to a corresponding mosaic of genotypes. We investigated the role of marsh-level characteristics in shaping a hybrid zone between two recently diverged avian taxa – Saltmarsh (Ammodramus caudacutus) and Nelson\u27s (A. nelsoni) sparrows. These species occupy different niches where allopatric, with caudacutus restricted to coastal marshes and nelsoni found in a broader array of wetland and grassland habitats and co-occur in tidal marshes in sympatry. We determined the influence of habitat types on the distribution of pure and hybrid sparrows and assessed the degree of overlap in the ecological niche of each taxon. To do this, we sampled and genotyped 305 sparrows from 34 marshes across the hybrid zone and from adjacent regions. We used linear regression to test for associations between marsh characteristics and the distribution of pure and admixed sparrows. We found a positive correlation between genotype and environmental variables with a patchy distribution of genotypes and habitats across the hybrid zone. Ecological niche models suggest that the hybrid niche was more similar to that of A. nelsoni and habitat suitability was influenced strongly by distance from coastline. Our results support a mosaic model of hybrid zone maintenance, suggesting a role for local environmental features in shaping the distribution and frequency of pure species and hybrids across space

Genotype-environment associations support a mosaic hybrid zone between two tidal marsh birds

Local environmental features can shape hybrid zone dynamics when hybrids are bounded by ecotones or when patchily distributed habitat types lead to a corresponding mosaic of genotypes. We investigated the role of marsh-level characteristics in shaping a hybrid zone between two recently diverged avian taxa – Saltmarsh (Ammodramus caudacutus) and Nelson\u27s (A. nelsoni) sparrows. These species occupy different niches where allopatric, with caudacutus restricted to coastal marshes and nelsoni found in a broader array of wetland and grassland habitats and co-occur in tidal marshes in sympatry. We determined the influence of habitat types on the distribution of pure and hybrid sparrows and assessed the degree of overlap in the ecological niche of each taxon. To do this, we sampled and genotyped 305 sparrows from 34 marshes across the hybrid zone and from adjacent regions. We used linear regression to test for associations between marsh characteristics and the distribution of pure and admixed sparrows. We found a positive correlation between genotype and environmental variables with a patchy distribution of genotypes and habitats across the hybrid zone. Ecological niche models suggest that the hybrid niche was more similar to that of A. nelsoni and habitat suitability was influenced strongly by distance from coastline. Our results support a mosaic model of hybrid zone maintenance, suggesting a role for local environmental features in shaping the distribution and frequency of pure species and hybrids across space