Strongly modulated transmissions in gapped armchair graphene nanoribbons with sidearm or on-site gate voltage

We propose two schemes of field-effect transistor based on gapped armchair graphene nanoribbons connected to metal leads, by introducing sidearms or on-site gate voltages. We make use of the band gap to reach excellent switch-off character. By introducing one sidearm or on-site gate to the graphene nanoribbon, conduction peaks appear inside the gap regime. By further applying two sidearms or on-site gates, these peaks are broadened to conduction plateaus with a wide energy window, thanks to the resonance from the dual structure. The position of the conduction windows inside the gap can be fully controlled by the length of the sidearms or the on-site gate voltages, which allows "on" and "off" operations for a specific energy window inside the gap regime. The high robustness of both the switch-off character and the conduction windows is demonstrated and shows the feasibility of the proposed dual structures for real applications.Comment: 6 pages, 6 figure

The Quantum Dynamics of Heterotic Vortex Strings

We study the quantum dynamics of vortex strings in N=1 SQCD with U(N_c) gauge group and N_f=N_c quarks. The classical worldsheet of the string has N=(0,2) supersymmetry, but this is broken by quantum effects. We show how the pattern of supersymmetry breaking and restoration on the worldsheet captures the quantum dynamics of the underlying 4d theory. We also find qualitative matching of the meson spectrum in 4d and the spectrum on the worldsheet.Comment: 13 page

Professionalizing criminal investigation: an examination of an early attempt to support specialization in criminal investigation

This article explores perceptions of individuals involved in an early attempt to professionalize detective work in Kent, UK. In 2000, Kent Police developed a Strategic Policing Doctrine incorporating a learning and development strategy. These ideas resulted in a partnership between Kent Police and Canterbury Christ Church University producing the Advanced Detective Training (ADT) programme including a university qualification, the BSc (Hons) in Applied Criminal Investigation delivered between 2001 and 2006. This research, conducted in 2016, used semi-structured interviews with 27 participants including: trainers, academic staff, students, and the Chief Constable. The research revealed that there were challenges in the selection of candidates, use of the term ‘advanced’ in the programme title and the abstraction of ADT trainees. A very high proportion of ADT officers valued the ‘training’ part of the programme with the majority valuing the ‘academic input’. This research provides a useful analysis of previous attempts to develop detective professionalization and accredited learning relevant for programme designers responding to the introduction of the Police Education Qualification Framework and direct entry and fast track detective training

Women police leaders in Europe: a tale of prejudice and patronage

This paper provides rich and unique insights into the experiences of women police leaders across seven European regions. Drawing on interview data it presents accounts of women’s experiences of pursuing advancement in policing and identifies informal and formal barriers to female advancement in European police organisations. Women police leaders report high levels of gender discrimination, obstruction and prejudice over the course of their careers. It argues that there are a number of subjective and informal criteria of ‘acceptability’ that shape women’s experiences of promotion and that informal patronage is a strong basis from which strategic appointments are made within European police systems. The paper makes sense of the ways in which informal aspects of career progression function alongside formal promotion criteria to preserve men as the ‘ideal’ candidates for police leadership positions, resulting in a preference for other men and the exclusion of women. The relevance of these findings is key to informing the future selection and development of police leaders in an increasingly complex police landscape

Fidelity, fidelity susceptibility and von Neumann entropy to characterize the phase diagram of an extended Harper model

For an extended Harper model, the fidelity for two lowest band edge states corresponding to different model parameters, the fidelity susceptibility and the von Neumann entropy of the lowest band edge states, and the spectrum-averaged von Neumann entropy are studied numerically, respectively. The fidelity is near one when parameters are in the same phase or same phase boundary; otherwise it is close to zero. There are drastic changes in fidelity when one parameter is at phase boundaries. For fidelity susceptibility the finite scaling analysis performed, the critical exponents $\alpha$, $\beta$, and $\nu$ depend on system sizes for the metal-metal phase transition, while not for the metal-insulator phase transition. For both phase transitions $\nu/\alpha\approx2$. The von Neumann entropy is near one for the metallic phase, while small for the insulating phase. There are sharp changes in von Neumann entropy at phase boundaries. According to the variation of the fidelity, fidelity susceptibility, and von Neumann entropy with model parameters, the phase diagram, which including two metallic phases and one insulating phase separated by three critical lines with one bicritical point, can be completely characterized, respectively. These numerical results indicate that the three quantities are suited for revealing all the critical phenomena in the model.Comment: 9 pages, 12 figure

Ultrafast response of surface electromagnetic waves in an aluminum film perforated with subwavelength hole arrays

The ultrafast dynamics of surface electromagnetic waves photogenerated on aluminum film perforated with subwavelength holes array was studied in the visible spectral range by the technique of transient photomodulation with 100 fs time resolution. We observed a pronounced blueshift of the resonant transmission band that reveals the important role of plasma attenuation in the optical response of nanohole arrays. The blueshift is inconsistent with plasmonic mechanism of extraordinary transmission and points to the crucial role of interference in the formation of transmission bands. The transient photomodulation spectra were successfully modeled within the Boltzmann equation approach for the electron-phonon relaxation dynamics, involving non-equilibrium hot electrons and quasi-equilibrium phonons.Comment: 4 pages, 3 figure

Heterotic Vortex Strings

We determine the low-energy N=(0,2) worldsheet dynamics of vortex strings in a large class of non-Abelian N=1 supersymmetric gauge theories.Comment: 44 pages, 3 figures. v2: typos corrected, reference adde