A theoretical understanding of the enigmatic linear-in-temperature (T) resistivity, ubiquitous in strongly correlated metallic systems, has been a long sought-after goal. Furthermore, the slope of this robust T-linear resistivity is also observed to stay constant through crossovers between different temperature regimes: A phenomenon we dub "slope invariance."Recently, several solvable models with T-linear resistivity have been proposed, putting us in an opportune moment to compare their inner workings in various explicit calculations.

We analyze the out-of-time-order correlation functions of a solvable model of a large number N of M-component quantum rotors coupled by Gaussian-distributed random, infinite-range exchange interactions. We focus on the growth of commutators of operators at a temperature T above the zero temperature quantum critical point separating the spin-glass and paramagnetic phases. In the large N,M limit, the squared commutators of the rotor fields do not display any exponential growth of commutators, in spite of the absence of any sharp quasiparticlelike excitations in the disorder-averaged theory.

The interconversion of charge and spin currents via spin-Hall effect is essential for spintronics. Energy-efficient and deterministic switching of magnetization can be achieved when spin polarizations of these spin currents are collinear with the magnetization. However, symmetry conditions generally restrict spin polarizations to be orthogonal to both the charge and spin flows. Spin polarizations can deviate from such direction in nonmagnetic materials only when the crystalline symmetry is reduced.

Motivated by multiple possible physical realizations, we study the SU(4) quantum antiferromagnet with a fundamental representation on each site of the triangular lattice. We provide evidence for a gapless liquid ground state of this system with an emergent Fermi surface of fractionalized fermionic partons coupled with a U(1) gauge field. Our conclusions are based on numerical simulations using the density matrix renormalization group method, which we support with a field theory analysis. © 2020 American Physical Society.

Students’ positions within the social network of a physics classroom have been shown to correlate with students’ sense of belonging, performance, and persistence in physics. Current research in PER aims to understand how different types of active learning classrooms promote the development of students’ social networks. In this work, we begin to examine how these networks develop in introductory physics labs where there is typically ample space and freedom for students to interact with their peers and build a community of learners.

In physics lab groups, students experience a wide range of equitable and inequitable interactions. After observing videos of students collaborating in an introductory physics lab, we defined that an equitable group is one in which every student’s bids are heard by their peers. We developed a methodology to characterize different lab groups by tracking students’ bid exchanges and assessing their levels of inchargeness.

Tissue-engineered cartilage has shown promising results in the repair of focal cartilage defects. However, current clinical techniques rely on an extra surgical procedure to biopsy healthy cartilage to obtain human chondrocytes. Alternatively, induced pluripotent stem cells (iPSCs) have the ability to differentiate into chondrocytes and produce cartilaginous matrix without the need to biopsy healthy cartilage. However, the mechanical properties of tissue-engineered cartilage with iPSCs are unknown and might be critical to long-term tissue function and health.

Solid-state quantum emitters can be used as nanoscale optical transducers in quantum metrology. Here, we present a technique to probe voltage controlled magnetic exchange fields with a quantum emitter embedded in a WSe2/ferromagnet heterostrucutre. © OSA 2020.

Problematizing is a physics practice involving the articulation of a gap in understanding into a clear question or problem. Inquiry-based labs may be conducive to problematizing behaviors, as students often collect data that do not agree with simplified models or their intuitive predictions. In this study, we analyzed video of students performing a lab in which they find the acceleration of an object in flight to be different from what the presented models predict. We aimed to identify the various activities that groups engaged in upon recognizing this inconsistency.

. Instructional physics labs are critical junctures for many STEM majors to develop an understanding of experimentation in the sciences. Students can acquire useful experimental skills and grow their identities as scientists. However, many traditionally-instructed labs do not necessarily involve authentic physics experimentation features in their curricula. Recent research calls for a reformation in undergraduate labs to incorporate more student agency and choice in the learning processes. In our institution, we have adopted open-ended lab teaching in the introductory physics courses.