Hyperfine interaction limits polarization entanglement of photons from semiconductor quantum dots

Excitons in quantum dots are excellent sources of polarization-entangled photon pairs, but a quantitative understanding of their interaction with the nuclear spin bath is still missing. Here we investigate the role of hyperfine energy shifts using experimentally accessible parameters and derive an upper limit to the achievable entanglement fidelity. Our results are consistent with all available literature, indicate that spin noise is often the dominant process limiting the entanglement in InGaAs quantum dots, and suggest routes to alleviate its effect

Detecting truth in suspect interviews: the effect of use of evidence (early and gradual) and time delay on Criteria-Based Content Analysis, Reality Monitoring and inconsistency within suspect statements

The strategic use of evidence in interviews with suspects has been shown to increase the ability of interviewers to accurately and consistently distinguish truthful from deceptive accounts. The present study considers the effect of early and gradual revelation of evidence by the interviewer, and the effect of shorter and longer delay on the verbal quality of truth-teller and liar statements within a mock crime paradigm. It was hypothesised that gradual disclosure of evidence (1) in terms of inconsistencies (a) within statements and (b) between statements and such evidence and (2) of the criteria of Criteria-Based Content Analysis (CBCA) and of Reality Monitoring (RM) would emphasise differences in the verbal quality of truth-teller and liar statements. Forty-two high school students took part in the study. The use of statement-evidence and within-statement inconsistency appears to be a robust cue to deception across interview style and delay. This indicates that gradual disclosure in interviews may increase interviewer accuracy in veracity decisions by eliciting statement inconsistencies. However, gradual revelation and delay affected the ability of CBCA and RM criteria to distinguish the veracity of suspect statements.N/

Electronic stopping of slow protons in oxides: Scaling properties

Electronic stopping of slow protons in ZnO, VO2 (metal and semiconductor phases), HfO2, and Ta2O5 was investigated experimentally. As a comparison of the resulting stopping cross sections (SCS) to data for Al2O3 and SiO2 reveals, electronic stopping of slow protons does not correlate with electronic properties of the specific material such as band gap energies. Instead, the oxygen 2p states are decisive, as corroborated by density functional theory calculations of the electronic densities of states. Hence, at low ion velocities the SCS of an oxide primarily scales with its oxygen density.Financial support of this work by the FWF (FWF-Project No. P22587-N20 and FWF-Project No. P25704-N20) is gratefully acknowledged. M. A. and J. I. J. acknowledge financial support by the Gobierno Vasco-UPV/EHU Project No. IT756-13, and the Spanish Ministerio de Economía y Competitividad (Grants No. FIS2013-48286-C02-02-P and FIS2016-76471-P). Fabrication and characterization of VO2 films at Vanderbilt University (CMG and RFH) was supported by a grant from the National Science Foundation (DMR-1207507). A research infrastructure fellowship of the Swedish Foundation for Strategic Research (SSF) under Contract No. RIF14-0053 supporting accelerator operation is acknowledged.Peer Reviewe