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This paper introduces the pilot implementation of the Evidence Based Personas survey instrument for assessing non-cognitive attributes of relevance from undergraduate students at different stages of their engineering degree for the purpose of informing proactive advising processes. The survey instrument was developed with two key objectives: first, to assess its potential for streamlining and shortening existing instruments, and second, to explore the possibility of consolidating items from different surveys that measure the same or closely related constructs. A proactive advising system is being developed that uses the Mediation Model of Research Experiences (MMRE) as a framework. Within this framework, participation in various educational activities is linked to increased Commitment to Engineering via three mediating parameters: Self-Efficacy, Teamwork/Leadership Self-Efficacy, and Engineering Identity. The existing, validated MMRE survey instrument was used as a starting point for development of the current instrument with a goal of streamlining / shortening the number of questions. Ultimately, we envision augmenting the shortened instrument with items related to broader non-cognitive and affective constructs from the SUCCESS instrument. Noting that both the MMRE and SUCCESS instruments include measures of Self-Efficacy and Engineering Identity, selected questions from both were included and compared. Data was collected from 395 total respondents, and subsequent data analysis was based on 337 valid participants. Factor Analysis techniques, both exploratory and confirmatory, were employed to uncover underlying or latent variables within the results, particularly in the areas of Self-Efficacy where the combined items of the SUCCESS instrument and the MMRE instrument were used. Cronbach’s alpha analysis was employed to assess the internal consistency of the survey instrument. The Teamwork, Engineering Identity, and Commitment to Engineering constructs all produced a Cronbach’s alpha value in excess of 0.80. The Self-Efficacy construct fell below the 0.80 threshold at 0.77 which is considered to be respectable but is indicative of some short comings compared to that of the other constructs. The results of the EFA four-factor pattern matrix show the SUCCESS instrument items breaking out into their own components while the MMRE items merge with some of the items from the Engineering Identity construct suggesting a distinction in the underlying concepts these items may be measuring. This finding is further supported in the CFA through an assessment of the Goodness of Fit (GFI), Tucker-Lewis Index (TLI), and Root Mean Square Error of Approximation (RMSEA) of these constructs. The initial groupings of the four constructs produced a robust CFI value of 0.853, robust TLI value of 0.838, and a robust RMSEA value of 0.075. Self-Efficacy is broken out into two sub-scales one defined by the three items from the SUCCESS instrument and the other defined by the four remaining items from the MMRE instrument. Engineering Identity was also broken into two sub-scales. The robust CFI and TLI report values of 0.928 and 0.919 respectively, and the robust RMSEA is reported to be 0.053. The findings of the factor analyses indicate that a shortened form of the MMRE survey instrument will provide reliable measures of the underlying constructs. Additionally, the results suggest that the self-efficacy as measured by items from the MMRE and from the SUCCESS instruments are related to two separate aspects of self-efficacy and do not load well into a single factor. 

Exciton-polariton lasers are a promising source of coherent light for low-energy applications due to their low-threshold operation. However, a detailed experimental study of their spectral purity, which directly affects their coherence properties, is still missing. Here, we present a high-resolution spectroscopic investigation of the energy and linewidth of an exciton-polariton laser in the single-mode regime, which derives its coherent emission from an optically pumped and confined exciton-polariton condensate. We report an ultra-narrow linewidth of 56 MHz or 0.24 µeV, corresponding to a coherence time of 5.7 ns. The narrow linewidth is consistently achieved by using an exciton-polariton condensate with a high photonic content confined in an optically induced trap. Contrary to previous studies, we show that the excitonic reservoir created by the pump and responsible for creating the trap does not strongly affect the emission linewidth as long as the condensate is trapped and the pump power is well above the condensation (lasing) threshold. The long coherence time of the exciton-polariton system uncovered here opens up opportunities for manipulating its macroscopic quantum state, which is essential for applications in classical and quantum computing. 

Strong interactions and topology drive a wide variety of correlated ground states. Some of the most interesting of these ground states, such as fractional quantum Hall states and fractional Chern insulators, have fractionally charged quasiparticles. Correlations in these phases are captured by the binding of electrons and vortices into emergent particles called composite fermions. Composite fermion quasiparticles are randomly localized at high levels of disorder and may exhibit charge order when there is not too much disorder in the system. However, more complex correlations are predicted when composite fermion quasiparticles cluster into a bubble, and then these bubbles order on a lattice. Such a highly correlated ground state is termed the bubble phase of composite fermions. Here we report the observation of such a bubble phase of composite fermions, evidenced by the re-entrance of the fractional quantum Hall effect. We associate this re-entrance with a bubble phase with two composite fermion quasiparticles per bubble. Our results demonstrate the existence of a new class of strongly correlated topological phases driven by clustering and charge ordering of emergent quasiparticles. 

Abstract Domain walls in fractional quantum Hall ferromagnets are gapless helical one-dimensional channels formed at the boundaries of topologically distinct quantum Hall (QH) liquids. Naïvely, these helical domain walls (hDWs) constitute two counter-propagating chiral states with opposite spins. Coupled to an s-wave superconductor, helical channels are expected to lead to topological superconductivity with high order non-Abelian excitations^1–3. Here we investigate transport properties of hDWs in theν = 2/3 fractional QH regime. Experimentally we found that current carried by hDWs is substantially smaller than the prediction of the naïve model. Luttinger liquid theory of the system reveals redistribution of currents between quasiparticle charge, spin and neutral modes, and predicts the reduction of the hDW current. Inclusion of spin-non-conserving tunneling processes reconciles theory with experiment. The theory confirms emergence of spin modes required for the formation of fractional topological superconductivity. 

Topological insulators are a class of electronic materials exhibiting robust edge states immune to perturbations and disorder. This concept has been successfully adapted in photonics, where topologically nontrivial waveguides and topological lasers were developed. However, the exploration of topological properties in a given photonic system is limited to a fabricated sample, without the flexibility to reconfigure the structurein situ. Here, we demonstrate an all-optical realization of the orbital Su–Schrieffer–Heeger model in a microcavity exciton-polariton system, whereby a cavity photon is hybridized with an exciton in a GaAs quantum well. We induce a zigzag potential for exciton polaritons all-optically by shaping the nonresonant laser excitation, and measure directly the eigenspectrum and topological edge states of a polariton lattice in a nonlinear regime of bosonic condensation. Furthermore, taking advantage of the tunability of the optically induced lattice, we modify the intersite tunneling to realize a topological phase transition to a trivial state. Our results open the way to study topological phase transitions on-demand in fully reconfigurable hybrid photonic systems that do not require sophisticated sample engineering.