Does Where You Work and What You Do Matter? Testing the Role of Organizational Context and Job Type for Future Study of Occupation-Based Secondary Trauma Intervention Development.

Organizational context (e.g., criminal justice, community-based, and healthcare) and job type (e.g., police, social workers, and healthcare providers) may impact the extent of occupation-based secondary trauma (OBST). Survey data collected from a multiphase community-based participatory research project were analyzed from a variety of professionals, who were likely to "encounter the consequences of traumatic events as part of their professional responsibilities" (n = 391, women = 55%, White = 92%). Results document high trauma exposure (adverse childhood experiences [ACEs] and workplace) and OBST-related outcomes (Maslach Burnout Inventory, Secondary Traumatic Stress Scale, post-traumatic stress disorder symptom checklist for DSM-5) for the entire sample with important differences across organizational context and job type. Using multivariate regression, the strongest determinants of suffering, however, were not related to a provider's specific profession but to their number of years on the job and their ACEs (e.g., adjusted R2 = 0.23, b = 2.01, p < .001). Likewise, the most protective factors were not profession specific but rather the provider's age and perceived effectiveness of OBST-related training (e.g., b = 2.26, p < .001). These findings inform intervention development and have implications for rural and other often under-resourced areas, where the same OBST-related intervention could potentially serve many different types of providers and organizations.

Particle-Hole Asymmetry in the Cuprate Pseudogap Measured with Time-Resolved Spectroscopy.

One of the most puzzling features of high-temperature cuprate superconductors is the pseudogap state, which appears above the temperature at which superconductivity is destroyed. There remain fundamental questions regarding its nature and its relation to superconductivity. But to address these questions, we must first determine whether the pseudogap and superconducting states share a common property: particle-hole symmetry. We introduce a new technique to test particle-hole symmetry by using laser pulses to manipulate and measure the chemical potential on picosecond time scales. The results strongly suggest that the asymmetry in the density of states is inverted in the pseudogap state, implying a particle-hole asymmetric gap. Independent of interpretation, these results can test theoretical predictions of the density of states in cuprates.

Stimulated emission of Cooper pairs in a high-temperature cuprate superconductor.

The concept of stimulated emission of bosons has played an important role in modern science and technology, and constitutes the working principle for lasers. In a stimulated emission process, an incoming photon enhances the probability that an excited atomic state will transition to a lower energy state and generate a second photon of the same energy. It is expected, but not experimentally shown, that stimulated emission contributes significantly to the zero resistance current in a superconductor by enhancing the probability that scattered Cooper pairs will return to the macroscopically occupied condensate instead of entering any other state. Here, we use time- and angle-resolved photoemission spectroscopy to study the initial rise of the non-equilibrium quasiparticle population in a Bi2Sr2CaCu2O8+δ cuprate superconductor induced by an ultrashort laser pulse. Our finding reveals significantly slower buildup of quasiparticles in the superconducting state than in the normal state. The slower buildup only occurs when the pump pulse is too weak to deplete the superconducting condensate, and for cuts inside the Fermi arc region. We propose this is a manifestation of stimulated recombination of broken Cooper pairs, and signals an important momentum space dichotomy in the formation of Cooper pairs inside and outside the Fermi arc region.

Ultrafast quenching of electron-boson interaction and superconducting gap in a cuprate superconductor.

Ultrafast spectroscopy is an emerging technique with great promise in the study of quantum materials, as it makes it possible to track similarities and correlations that are not evident near equilibrium. Thus far, however, the way in which these processes modify the electron self-energy--a fundamental quantity describing many-body interactions in a material--has been little discussed. Here we use time- and angle-resolved photoemission to directly measure the ultrafast response of self-energy to near-infrared photoexcitation in high-temperature cuprate superconductor. Below the critical temperature of the superconductor, ultrafast excitations trigger a synchronous decrease of electron self-energy and superconducting gap, culminating in a saturation in the weakening of electron-boson coupling when the superconducting gap is fully quenched. In contrast, electron-boson coupling is unresponsive to ultrafast excitations above the critical temperature of the superconductor and in the metallic state of a related material. These findings open a new pathway for studying transient self-energy and correlation effects in solids.