Coherence measurements of polaritons in thermal equilibrium reveal a power law for two-dimensional condensates.

We have created a spatially homogeneous polariton condensate in thermal equilibrium, up to very high condensate fraction. Under these conditions, we have measured the coherence as a function of momentum and determined the total coherent fraction of this boson system from very low density up to density well above the condensation transition. These measurements reveal a consistent power law for the coherent fraction as a function of the total density over nearly three orders of its magnitude. The same power law is seen in numerical simulations solving the two-dimensional Gross-Pitaevskii equation for the equilibrium coherence.

The prevalence of human papillomavirus in ocular surface squamous neoplasia in HIV positive and negative patients in a South African population.

PURPOSE: To assess the prevalence and subtypes of Human Papillomavirus (HPV) in Ocular Surface Squamous Neoplasia (OSSN) in Human Immunodeficiency Virus (HIV) positive and negative patients in South Africa. BASIC PROCEDURES: This study was a single center retrospective cross-sectional study, conducted at Tygerberg Hospital, Western Cape, South Africa. We assessed 63 histopathologically confirmed OSSN formalin-fixed paraffin-embedded (FFPE) tissue blocks from 2015-2023. The presence of HPV was determined using the Hybrispot Direct Flow Chip Kit. Corresponding clinical data was retrieved from the National Health Laboratory Service (NHLS) central data warehouse. MAIN FINDINGS: Of the confirmed OSSN samples, 66.7% tested positive for HPV (95% confidence interval [CI] 54-77.3%). Of the 42 HPV positive samples, 38 (90.5%) had one or more known genotypes detected and 4 had unknown genotypes. The most prevalent subtypes were HPV 11, 16 and 18 (found in 61.9%, 52.4% and 33.3% of HPV positive samples respectively). 88.9% of the lesions biopsied were from HIV positive patients, of whom 56.4% had a CD4 + count of < 200 cells/µL. A lower median CD4 + count was detected among HIV positive patients with invasive squamous cell carcinoma compared to those with moderate dysplasia (p < 0.0198). CONCLUSIONS: There is a high prevalence of HPV in OSSN in South Africa. Certain subtypes namely, 11, 16, 18, 31, 33 and 35 may be more carcinogenic. HIV with HPV co-infection may be linked as a causative factor in the development of OSSN.

Deep Aphantasia: a visual brain with minimal influence from priors or inhibitory feedback?

The authors are both self-described congenital aphantasics, who feel they have never been able to have volitional imagined visual experiences during their waking lives. In addition, Loren has atypical experiences of a number of visual phenomena that involve an extrapolation or integration of visual information across space. In this perspective, we describe Loren's atypical experiences of a number of visual phenomena, and we suggest these ensue because her visual experiences are not strongly shaped by inhibitory feedback or by prior expectations. We describe Loren as having Deep Aphantasia, and Derek as shallow, as for both a paucity of feedback might prevent the generation of imagined visual experiences, but for Loren this additionally seems to disrupt activity at a sufficiently early locus to cause atypical experiences of actual visual inputs. Our purpose in describing these subjective experiences is to alert others to the possibility of there being sub-classes of congenital aphantasia, one of which-Deep Aphantasia, would be characterized by atypical experiences of actual visual inputs.

Evidence for chiral graviton modes in fractional quantum Hall liquids.

Exotic physics could emerge from interplay between geometry and correlation. In fractional quantum Hall (FQH) states1, novel collective excitations called chiral graviton modes (CGMs) are proposed as quanta of fluctuations of an internal quantum metric under a quantum geometry description2-5. Such modes are condensed-matter analogues of gravitons that are hypothetical spin-2 bosons. They are characterized by polarized states with chirality6-8 of +2 or -2, and energy gaps coinciding with the fundamental neutral collective excitations (namely, magnetorotons9,10) in the long-wavelength limit. However, CGMs remain experimentally inaccessible. Here we observe chiral spin-2 long-wavelength magnetorotons using inelastic scattering of circularly polarized lights, providing strong evidence for CGMs in FQH liquids. At filling factor v = 1/3, a gapped mode identified as the long-wavelength magnetoroton emerges under a specific polarization scheme corresponding to angular momentum S = -2, which persists at extremely long wavelength. Remarkably, the mode chirality remains -2 at v = 2/5 but becomes the opposite at v = 2/3 and 3/5. The modes have characteristic energies and sharp peaks with marked temperature and filling-factor dependence, corroborating the assignment of long-wavelength magnetorotons. The observations capture the essentials of CGMs and support the FQH geometrical description, paving the way to unveil rich physics of quantum metric effects in topological correlated systems.

Critical fluctuations in a confined driven-dissipative quantum condensate.

Phase fluctuations determine the low-energy properties of quantum condensates. However, at the condensation threshold, both density and phase fluctuations are relevant. While strong emphasis has been given to the investigation of phase fluctuations, which dominate the physics of the quantum system away from the critical point, number fluctuations have been much less explored even in thermal equilibrium. In this work, we report experimental observation and theoretical description of fluctuations in a circularly confined nonequilibrium Bose-Einstein condensate of polaritons near the condensation threshold. We observe critical fluctuations, which combine the number fluctuations of a single-mode condensate state and competition between different states. The latter is analogous to mode hopping in photon lasers. Our theoretical analysis indicates that this phenomenon is of a quantum character, while classical noise of the pump is not sufficient to explain the experiments. The manifestation of a critical quantum state competition unlocks possibilities for the study of condensate formation while linking to practical realizations in photonic lasers.

Long-term quality of life outcomes in patients undergoing microsurgical resection of vestibular schwannoma.

Background: While previous studies have assessed patient reported quality of life (QOL) of various vestibular schwannoma (VS) treatment modalities, few studies have assessed QOL as related to the amount of residual tumor and need for retreatment in a large series of patients. Objective: To assess patient reported QOL outcomes following VS resection with a focus on extent of resection and retreatment. Methods: A retrospective chart review was performed using single-center institutional data of adult patients who underwent VS resection by the senior authors between 1989-2018 at Loyola University Medical Center. The Penn Acoustic Neuroma Quality of Life (PANQOL) survey was sent to all patients via postal mail. Results: Fifty-five percent of 367 total patients were female with a mean age of 61.6 years (SD 12.63). The mean period between surgery and PANQOL response was 11.4 years (IQR: 4.74-7.37). The median tumor size was 2 cm (IQR: 1.5-2.8). The mean total PANQOL score was 70 (SD 19). Patients who required retreatment reported lower overall scores (µdiff = -10.11, 95% CI: -19.48 to -0.74; p = 0.03) and face domain scores (µdiff = -20.34, 95% CI: -29.78 to -10.91; p < .001). There was no association between extent of resection and PANQOL scores in any domain. Conclusion: In an analysis of 367 patients who underwent microsurgical resection of VS, extent of resection did not affect PANQOL scores in contrast to previous reports in the literature, while the need for retreatment and facial function had a significant impact on patient-reported outcomes.

Is There a Plateau to the Learning Curve for Acoustic Neuroma Resection?-Experience and Outcomes from a Single Interdisciplinary Team Over Thirty Years.

Objective The evolution of acoustic neuroma (AN) care continues to shift focus on balancing optimized tumor resection and control with preservation of neurological function. Prior learning curve analyses of AN resection have demonstrated a plateau between 20 and 100 surgeries. In this study of 860 consecutive AN surgeries, we investigate the presence of an extended learning curve tail for AN resection. Methods A retrospective cohort study of AN resections by a single interdisciplinary team between 1988 and 2018 was performed. Proportional odds models and restricted cubic splines were used to determine the association between the timing of surgery and odds of improved postoperative outcomes. Results The likelihood of improved postoperative House-Brackmann (HB) scores increased in the first 400 procedures, with HB 1 at 36% in 1988 compared with 79% in 2004. While the probability of a better HB score increased over time, there was a temporary decrease in slope of the cubic spline between 2005 and 2009. The last 400 cases continued to see improvement in optimal HB outcomes: adjusted odds of HB 1 score were twofold higher in both 2005 to 2009 (adjusted odds ratio [aOR]: 2.11, 95% confidence interval [CI]: 1.38-3.22, p < 0.001) and 2010 to 2018 (aOR: 2.18, 95% CI: 1.49-3.19, p < 0.001). Conclusion In contrast to prior studies, our study demonstrates the steepest growth for learning, as measured by rates of preservation of facial function outcomes (HB 1), occurs in the first 400 AN resections. Additionally, improvements in patient outcomes continued even 30 years into practice, underlining the importance of lifelong learning.

Next-generation even-denominator fractional quantum Hall states of interacting composite fermions.

The discovery of the fractional quantum Hall state (FQHS) in 1982 ushered a new era of research in many-body condensed matter physics. Among the numerous FQHSs, those observed at even-denominator Landau level filling factors are of particular interest as they may host quasiparticles obeying non-Abelian statistics and be of potential use in topological quantum computing. The even-denominator FQHSs, however, are scarce and have been observed predominantly in low-disorder two-dimensional (2D) systems when an excited electron Landau level is half filled. An example is the well-studied FQHS at filling factor [Formula: see text] 5/2 which is believed to be a Bardeen-Cooper-Schrieffer-type, paired state of flux-particle composite fermions (CFs). Here, we report the observation of even-denominator FQHSs at [Formula: see text] 3/10, 3/8, and 3/4 in the lowest Landau level of an ultrahigh-quality GaAs 2D hole system, evinced by deep minima in longitudinal resistance and developing quantized Hall plateaus. Quite remarkably, these states can be interpreted as even-denominator FQHSs of CFs, emerging from pairing of higher-order CFs when a CF Landau level, rather than an electron or a hole Landau level, is half-filled. Our results affirm enhanced interaction between CFs in a hole system with significant Landau level mixing and, more generally, the pairing of CFs as a valid mechanism for even-denominator FQHSs, and suggest the realization of FQHSs with non-Abelian anyons.

Predictive extrapolation effects can have a greater impact on visual decisions, while visual adaptation has a greater impact on conscious visual experience.

Human vision is shaped by historic and by predictive processes. The lingering impact of visual adaptation, for instance, can act to exaggerate differences between past and present inputs, whereas predictive processes can promote extrapolation effects that allow us to anticipate the near future. It is unclear to what extent either of these effects manifest in changes to conscious visual experience. It is also unclear how these influences combine, when acting in concert or opposition. We had people make decisions about the sizes of inputs, and report on levels of decisional confidence. Tests were either selectively subject to size adaptation, to an extrapolation effect, or to both of these effects. When these two effects were placed in opposition, extrapolation had a greater impact on decision making. However, our data suggest the influence of extrapolation is primarily decisional, whereas size adaptation more fully manifests in changes to conscious visual awareness.

Anomalous High-Temperature Magnetoresistance in a Dilute 2D Hole System.

We report an unusual magnetoresistance that strengthens with the temperature in a dilute two-dimensional (2D) hole system in GaAs/AlGaAs quantum wells with densities p=1.98-0.99×10^{10}/cm^{2} where r_{s}, the ratio between Coulomb energy and Fermi energy, is as large as 20-30. We show that, while the system exhibits a negative parabolic magnetoresistance at low temperatures (≲0.4 K) characteristic of an interacting Fermi liquid, a positive magnetoresistance emerges unexpectedly at higher temperatures, and grows with increasing temperature even in the regime T∼E_{F}, close to the Fermi energy. This unusual positive magnetoresistance at high temperatures can be attributed to the viscous transport of 2D hole fluid in the hydrodynamic regime where holes scatter frequently with each other. These findings give insight into the collective transport of strongly interacting carriers in the r_{s}≫1 regime and new routes toward magnetoresistance at high temperatures.

Dynamic Response of Wigner Crystals.

The Wigner crystal, an ordered array of electrons, is one of the very first proposed many-body phases stabilized by the electron-electron interaction. We examine this quantum phase with simultaneous capacitance and conductance measurements, and observe a large capacitive response while the conductance vanishes. We study one sample with four devices whose length scale is comparable with the crystal's correlation length, and deduce the crystal's elastic modulus, permittivity, pinning strength, etc. Such a systematic quantitative investigation of all properties on a single sample has a great promise to advance the study of Wigner crystals.

Occipital Neuralgia following Acoustic Neuroma Resection.

Background While postoperative outcomes of acoustic neuroma (AN) resection commonly consider hearing preservation and facial function, headache is a critical quality of life factor. Postoperative headache is described in the literature; however, there is limited discussion specific to occipital neuralgia (ON) following AN resection. Objective The aim of this study is to investigate the effectiveness of conservative management and surgery. Methods We conducted a retrospective review of 872 AN patients who underwent resection at our institution between 1988 and 2017 and identified 15 patients (1.9%) that met International Classification of Headache Disorders criteria for ON. Results Of the 15 ON patients, surgical approaches included 13 (87%) retrosigmoid (RS), one (7%) translabyrinthine (TL), and one (7%) combined RS + TL. Mean clinical follow-up was 119 months (11-263). Six (40%) patients obtained pain relief through conservative management, while the remaining nine (60%) underwent surgery or ablative procedure. Three (38%) patients received an external neurolysis, four (50%) received a neurectomy, one (13%) had both procedures, and one (13%) received two C2 to 3 radio frequency ablations. Of the nine patients who underwent procedural ON treatment, seven (78%) patients achieved pain relief, one patient (11%) continued to have pain, and one patient (11%) was lost to follow-up. Of the six patients whose pain was controlled with conservative management and nerve blocks, five (83%) found relief by using neuropathic pain medication and one (17%) found relief on nonsteroidal anti-inflammatory drug. Conclusion Our series demonstrates success with conservative management in some, but overall a minority (40%) of patients, reserving decompression only for refractory cases.

Domain Textures in the Fractional Quantum Hall Effect.

Impacts of domain textures on low-lying neutral excitations in the bulk of fractional quantum Hall effect (FQHE) systems are probed by resonant inelastic light scattering. We demonstrate that large domains of quantum fluids support long-wavelength neutral collective excitations with well-defined wave vector (momentum) dispersion that could be interpreted by theories for uniform phases. Access to dispersive low-lying neutral collective modes in large domains of FQHE fluids such as long wavelength magnetorotons at filling factor v=1/3 offer significant experimental access to strong electron correlation physics in the FQHE.

Transport in helical Luttinger liquids in the fractional quantum Hall regime.

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 excitations1-3. Here we investigate transport properties of hDWs in the ν = 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.

Findings From a Provider-Led, Mindfulness-Based, Internet-Streamed Yoga Video Addressing the Psychological Outcomes of Breast Cancer Survivors.

The aim of this study was to explore the psychological outcomes of a mindfulness-based Internet-streamed yoga video in breast cancer survivors. A one-group, repeated-measures, purposive sample using a directed qualitative descriptive and convergent mixed-methods approach was used. Participants were recruited from breast oncology practices across 2 settings in the northeastern United States in April 2019. Education about the video was provided, and the link to the video was sent to participants. Demographic information, Knowing Participation in Change Short Form (KPCSF), Short Warwick-Edinburgh Mental Well-being Scale (WEMWBS), and the Generalized Anxiety Distress Scale (GAD-7) were obtained at baseline and at 2 and 4 weeks. A semistructured interview was conducted at 4 weeks. Thirty-five women (mean age = 56 years) participated. A one-group, repeated-measures analysis of variance indicated statistically significant changes occurred in all measures between week 0 and week 4: decreased GAD (t = -2.97, P = .004), improved WEMWBS (t = 2.52, P = .008), and increased KPC (t = 2.99, P = .004). Qualitative findings suggest the overall experience of the video was positive and the women would recommend its use to others. Improvements in all psychological measures were achieved with video use. Findings indicate an improvement in psychological measures and support the theory of Knowing Participation in Change. This work further contributes to accessible, flexible interventions available through the Internet and/or mobile applications aimed at improving breast cancer survivorship.

Observation of Flat Bands in Gated Semiconductor Artificial Graphene.

Flat bands near M points in the Brillouin zone are key features of honeycomb symmetry in artificial graphene (AG) where electrons may condense into novel correlated phases. Here we report the observation of van Hove singularity doublet of AG in GaAs quantum well transistors, which presents the evidence of flat bands in semiconductor AG. Two emerging peaks in photoluminescence spectra tuned by backgate voltages probe the singularity doublet of AG flat bands and demonstrate their accessibility to the Fermi level. As the Fermi level crosses the doublet, the spectra display dramatic stability against electron density, indicating interplays between electron-electron interactions and honeycomb symmetry. Our results provide a new flexible platform to explore intriguing flat band physics.

Three-dimensional reconstruction of porous polymer films from FIB-SEM nanotomography data using random forests.

Combined focused ion beam and scanning electron microscope (FIB-SEM) tomography is a well-established technique for high resolution imaging and reconstruction of the microstructure of a wide range of materials. Segmentation of FIB-SEM data is complicated due to a number of factors; the most prominent is that for porous materials, the scanning electron microscope image slices contain information not only from the planar cross-section of the material but also from underlying, exposed subsurface pores. In this work, we develop a segmentation method for FIB-SEM data from ethyl cellulose porous films made from ethyl cellulose and hydroxypropyl cellulose (EC/HPC) polymer blends. These materials are used for coating pharmaceutical oral dosage forms (tablets or pellets) to control drug release. We study three samples of ethyl cellulose and hydroxypropyl cellulose with different volume fractions where the hydroxypropyl cellulose phase has been leached out, resulting in a porous material. The data are segmented using scale-space features and a random forest classifier. We demonstrate good agreement with manual segmentations. The method enables quantitative characterization and subsequent optimization of material structure for controlled release applications. Although the methodology is demonstrated on porous polymer films, it is applicable to other soft porous materials imaged by FIB-SEM. We make the data and software used publicly available to facilitate further development of FIB-SEM segmentation methods. LAY DESCRIPTION: For imaging of very fine structures in materials, the resolution limits of, e.g. X-ray computed tomography quickly become a bottleneck. Scanning electron microscopy (SEM) provides a way out, but it is essentially a two-dimensional imaging technique. One manner in which to extend it to three dimensions is to use a focused ion beam (FIB) combined with a scanning electron microscopy and acquire tomography data. In FIB-SEM tomography, ions are used to perform serial sectioning and the electron beam is used to image the cross section surface. This is a well-established method for a wide range of materials. However, image analysis of FIB-SEM data is complicated for a variety of reasons, in particular for porous media. In this work, we analyse FIB-SEM data from ethyl cellulose porous films made from ethyl cellulose and hydroxypropyl cellulose (EC/HPC) polymer blends. These films are used as coatings for controlled drug release. The aim is to perform image segmentation, i.e. to identify which parts of the image data constitute the pores and the solid, respectively. Manual segmentation, i.e. when a trained operator manually identifies areas constituting pores and solid, is too time-consuming to do in full for our very large data sets. However, by performing manual segmentation on a set of small, random regions of the data, we can train a machine learning algorithm to perform automatic segmentation on the entire data sets. The method yields good agreement with the manual segmentations and yields porosities of the entire data sets in very good agreement with expected values. The method facilitates understanding and quantitative characterization of the geometrical structure of the materials, and ultimately understanding of how to tailor the drug release.

3D high spatial resolution visualisation and quantification of interconnectivity in polymer films.

A porous network acts as transport paths for drugs through films for controlled drug release. The interconnectivity of the network strongly influences the transport properties. It is therefore important to quantify the interconnectivity and correlate it to transport properties for control and design of new films. This work presents a novel method for 3D visualisation and analysis of interconnectivity. High spatial resolution 3D data on porous polymer films for controlled drug release has been acquired using a focused ion beam (FIB) combined with a scanning electron microscope (SEM). The data analysis method enables visualisation of pore paths starting at a chosen inlet pore, dividing them into groups by length, enabling a more detailed quantification and visualisation. The method also enables identification of central features of the porous network by quantification of channels where pore paths coincide. The method was applied to FIB-SEM data of three leached ethyl cellulose (EC)/hydroxypropyl cellulose (HPC) films with different weight percentages. The results from the analysis were consistent with the experimentally measured release properties of the films. The interconnectivity and porosity increase with increasing amount of HPC. The bottleneck effect was strong in the leached film with lowest porosity.

Quantum hydrodynamics of a single particle.

Semiconductor devices are strong competitors in the race for the development of quantum computational systems. In this work, we interface two semiconductor building blocks of different dimensionalities with complementary properties: (1) a quantum dot hosting a single exciton and acting as a nearly ideal single-photon emitter and (2) a quantum well in a 2D microcavity sustaining polaritons, which are known for their strong interactions and unique hydrodynamic properties, including ultrafast real-time monitoring of their propagation and phase mapping. In the present experiment, we can thus observe how the injected single particles propagate and evolve inside the microcavity, giving rise to hydrodynamic features typical of macroscopic systems despite their genuine intrinsic quantum nature. In the presence of a structural defect, we observe the celebrated quantum interference of a single particle that produces fringes reminiscent of wave propagation. While this behavior could be theoretically expected, our imaging of such an interference pattern, together with a measurement of antibunching, constitutes the first demonstration of spatial mapping of the self-interference of a single quantum particle impinging on an obstacle.