Embryogenesis is guided by a limited set of signaling pathways dynamically expressed in different places. How a context-dependent signaling response is generated has been a central question of developmental biology, which can now be addressed with in vitro models of human embryos that are derived from embryonic stem cells (hESCs). Our previous work demonstrated that during early stages of hESC differentiation, cells chronicle signaling hierarchy.

Motivated by cold-atom experiments and a desire to understand far-from-equilibrium quantum transport, we analytically study the dynamics of spin helices in the one-dimensional XX model. We use a Jordan-Wigner transformation to map the spin chain onto a noninteracting Fermi gas with simple equations of motion. The resulting dynamics are nontrivial, however, as the spin-helix initial condition corresponds to a highly nonequilibrium distribution of the fermions. We find a separation of timescales between the in-plane and out-of-plane spin dynamics.

The observation of superconductivity and correlated insulating states in twisted bilayer graphene has motivated much theoretical progress at integer fillings. However, little attention has been given to fractional fillings. Here we show that the three-peak structure of Wannier orbitals, dictated by the symmetry and topology of flat bands, facilitates the emergence of a state we name a “fractional correlated insulator” at commensurate fractional filling of ν = n ± 1/3.

Functional properties of transition-metal oxides strongly depend on crystallographic defects; crystallographic lattice deviations can affect ionic diffusion and adsorbate binding energies. Scanning x-ray nanodiffraction enables imaging of local structural distortions across an extended spatial region of thin samples. Yet, localized lattice distortions remain challenging to detect and localize using nanodiffraction, due to their weak diffuse scattering.

Variational approaches are among the most powerful techniques to approximately solve quantum many-body problems. These encompass both variational states based on tensor or neural networks, and parameterized quantum circuits in variational quantum eigensolvers. However, self-consistent evaluation of the quality of variational wavefunctions is a notoriously hard task. Using a recently developed Hamiltonian reconstruction method, we propose a multi-faceted approach to evaluating the quality of neural-network based wavefunctions.

Prior work has found inequities in what experimental roles students take on during instructional labs. Research also suggests that this role division might arise implicitly and that prompting explicit role negotiation might improve equity in lab group work. To understand these various ways students negotiate roles in their lab groups, we use the lens of positioning to analyze two different video episodes of a gender-and-race-diverse group of three students.

Natural language processing (NLP) has the capacity to increase the scale and efficiency of content analysis in Physics Education Research. One promise of this approach is the possibility of implementing coding schemes on large data sets taken from diverse contexts. Applying NLP has two main challenges, however. First, a large initial human-coded data set is needed for training, though it is not immediately clear how much training data are needed. Second, if new data are taken from a different context from the training data, automated coding may be impacted in unpredictable ways.

While understanding laboratory equipment is an important learning goal of physics laboratory (lab) instruction, previous studies have found inequities as to who gets to use equipment in in-person lab classes. With the transition to remote learning during the COVID-19 pandemic, class dynamics changed and the effects on equipment usage remain unclear. As part of a larger effort to make intro physics labs more equitable, we investigated student equipment usage based on gender and race in two introductory physics lab courses, one taught in-person and one taught remotely.

Numerous studies have identified gender inequity in how students divide roles in lab courses. Few studies, however, have probed how these inequities impact women’s experimental physics identity development. In this work, we used closed-response surveys to investigate which lab tasks students view as part of “doing physics” and how these designations varied by gender. In both courses, we found that most students viewed working with the experimental apparatus, taking lab notes, doing data analysis, and thinking about the physics theory behind the experiment as part of doing physics.

Research has shown that students in inquiry-based physics labs often expect their experiment to verify a known theory or model, contrary to the goals of the lab. It is important, therefore, to identify ways for instructors to shift students’ expectations or epistemic frames to those in line with scientific inquiry. In this paper, we analyze video recordings of one inquiry-based lab session in which the instructor intentionally encourages students to falsify, or disprove, the claim under investigation.