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The current research evaluates user experience and preference when interacting with a patient-reported outcome measure (PROM) healthcare application displayed on a single tablet in comparison to interaction with the same application distributed across two tablets. We conducted a within-subject user study with 43 participants who engaged with and rated the usability of our system and participated in a post-experiment interview to collect subjective data. Our findings showed significantly higher usability and higher pragmatic quality ratings for the single tablet condition. However, some users attribute a higher level of presence to the avatar and prefer it to be placed on a second tablet., Comment: In 30th ACM Symposium on Virtual Reality Software and Technology (VRST 2024)

This study will investigate the user experience while interacting with highly photorealistic virtual job interviewer avatars in Virtual Reality (VR), Augmented Reality (AR), and on a 2D screen. Having a precise speech recognition mechanism, our virtual character performs a mock-up software engineering job interview to adequately immerse the user in a life-like scenario. To evaluate the efficiency of our system, we measure factors such as the provoked level of anxiety, social presence, self-esteem, and intrinsic motivation. This research is a work in progress with a prospective within-subject user study including approximately 40 participants. All users will engage with three job interview conditions (VR, AR, and desktop) and provide their feedback. Additionally, users' bio-physical responses will be collected using a biosensor to measure the level of anxiety during the job interview., Comment: 2-page ISMAR poster paper

Lead halide perovskites have emerged as highly efficient solar cell materials. However, to date, the most promising members of this class are polymorphs, in which a wide-band gap $\delta$ phase competes with the photoactive perovskite $\alpha$ form, and the intrinsic physical interactions that stabilize one phase over the other are currently not well understood. Classical molecular dynamics simulations based on suitably parameterized force fields (FF) enable computational studies over broad temperature (and pressure) ranges and can help to identify the underlying factors that govern relative phase stability at the atomic level. In this article, we present a polarizable (pol) as well as a non-polarizable (npol) FF for the all-inorganic lead halide material CsPbI$_3$ as a prototype system exhibiting a $\delta$/$\alpha$ polymorphism. Both npol and pol FFs have been determined using a force-matching approach based on reference data from first-principles molecular dynamics simulations over a wide range of temperatures. While both FFs are able to describe the perovskite as well as the non-perovskite phase, finer structural details as well as the relative phase stability are better reproduced with the polarizable version. A comparison of these ab initio-derived interatomic potentials allows direct insights into the physical origin of the interactions that govern the interplay between the two competing phases. It turns out that explicit polarization is the essential factor that stabilizes the strongly anisotropic $\delta$ phase over the high symmetry perovskite $\alpha$ phase at lower temperatures. This fundamental difference between $\alpha$ and $\delta$ phase appears universal and might thus also hold for other perovskite compounds with $\delta$/$\alpha$ polymorphism and thus provide rational guidance for synthetic efforts to stabilize the photoactive perovskite phase at room temperature., Comment: 40 pages, 6 figures

Within biological fluid dynamics, it is conventional to distinguish between "puller" and "pusher" microswimmers on the basis of the forward or aft location of the flagella relative to the cell body: typically, bacteria are pushers and algae are pullers. Here we note that since many pullers have "outboard" cilia or flagella displaced laterally from the cell centerline on both sides of the organism, there are two important subclasses whose far-field is that of a stresslet, but whose near field is qualitatively more complex. The ciliary beat creates not only a propulsive force but also swirling flows that can be represented by paired rotlets with two possible senses of rotation, either "feeders" that sweep fluid toward the cell apex, or "expellers" that push fluid away. Experimental studies of the rotifer $Brachionus~plicatilis$ in combination with earlier work on the green algae $Chlamydomonas~reinhardtii$ show that the two classes have markedly different interactions with surfaces. When swimming near a surface, expellers such as $C.~reinhardtii$ scatter from the wall, whereas a feeder like $B.~plicatilis$ stably attaches. This results in a stochastic "run-and-stick" locomotion, with periods of ballistic motion parallel to the surface interrupted by trapping at the surface., Comment: 16 pages, 6 figures, supplementary videos available at website of REG

We consider quantum spin chains with a hidden free fermionic structure, distinct from the Jordan-Wigner transformation and its generalizations. We express selected local operators with the hidden fermions. This way we can exactly solve the real time dynamics in various physical scenarios, including the computation of selected dynamical two point functions and Loschmidt amplitudes, in continuous or discrete time. In the latter case we build quantum circuits that can be implemented on a quantum computer. With this we extend the family of classically simulable quantum many body processes., Comment: 6+10 pages, 1+3 figures

One of the most promising technologies inside the Extended Reality (XR) spectrum is Augmented Reality. This technology is already in people's pockets regarding Mobile Augmented Reality with their smartphones. The scientific community still needs answers about how humans could and should interact in environments where perceived stimuli are different from fully physical or digital circumstances. Moreover, it is still being determined if people accept these new technologies in different social environments and interaction settings or if some obstacles could exist. This paper explores the impact of the Social Environment and the Focus of social interaction on users while playing a location-based augmented reality game, measuring it with user experience and social acceptance indicators. An empirical study in a within-subject fashion was performed in different social environments and under different settings of social interaction focus with N = 28 participants compiling self-reported questionnaires after playing a Scavenger Hunt in Augmented Reality. The measures from two different Social Environments (Crowded vs. Uncrowded) resulted in statistically relevant mean differences with indicators from the Social Acceptability dimension. Moreover, the analyses show statistically relevant differences between the variances from different degrees of Social Interaction Focus with Overall Social Presence, Perceived Psychological Engagement, Perceived Attentional Engagement, and Perceived Emotional Contagion. The results suggest that a location-based AR game played in different social environments and settings can influence the user experience's social dimension. Therefore, they should be carefully considered while designing immersive technological experiences in public spaces involving social interactions between players.

The auditory sense of humans is important when it comes to navigation. The importance is especially high in cases when an object of interest is visually partly or fully covered. Interactions with users of technology are mainly focused on the visual domain of navigation tasks. This paper presents the results of a literature review and user study exploring the impact of spatial auditory navigation on user experience during an augmented outdoor navigation task. For the user test, participants used an augmented reality app guiding them to different locations with different digital augmentation. We conclude that the utilization of the auditory sense is yet still underrepresented in augmented reality applications. In the future, more usage scenarios for audio-augmented reality such as navigation will enhance user experience and interaction quality.

Technology presents a significant educational opportunity, particularly in enhancing emotional engagement and expanding learning and educational prospects for individuals with Neurodevelopmental Disorders (NDD). Virtual reality emerges as a promising tool for addressing such disorders, complemented by numerous touchscreen applications that have shown efficacy in fostering education and learning abilities. VR and touchscreen technologies represent diverse interface modalities. This study primarily investigates which interface, VR or touchscreen, more effectively facilitates food education for individuals with NDD. We compared learning outcomes via pre- and post-exposure questionnaires. To this end, we developed GEA, a dual-interface, user-friendly web application for Food Education, adaptable for either immersive use in a head-mounted display (HMD) or non-immersive use on a tablet. A controlled study was conducted to determine which interface better promotes learning. Over three sessions, the experimental group engaged with all GEA games in VR (condition A), while the control group interacted with the same games on a tablet (condition B). Results indicated a significant increase in post-questionnaire scores across subjects, averaging a 46% improvement. This enhancement was notably consistent between groups, with VR and Tablet groups showing 42% and 41% improvements, respectively., Comment: 15 pages, 1 figure, 4 tables, Conference HCII24

Neurodevelopmental disorders (NDD), encompassing conditions like Intellectual Disability, Attention Deficit Hyperactivity Disorder, and Autism Spectrum Disorder, present challenges across various cognitive capacities. Attention deficits are often common in individuals with NDD due to the sensory system dysfunction that characterizes these disorders. Consequently, limited attention capability can affect the overall quality of life and the ability to transfer knowledge from one circumstance to another. The literature has increasingly recognized the potential benefits of virtual reality (VR) in supporting NDD learning and rehabilitation due to its interactive and engaging nature, which is critical for consistent practice. In previous studies, we explored the usage of a VR application called Wildcard to enhance attention skills in persons with NDD. The application has been redesigned in this study, exploiting eye-tracking technology to enable novel and more fine-grade interactions. A four-week experiment with 38 NDD participants was conducted to evaluate its usability and effectiveness in improving Visual Attention Skills. Results show the usability and effectiveness of Wildcard in enhancing attention skills, advocating for continued exploration of VR and eye-tracking technology's potential in NDD interventions., Comment: 15 pages, 6 figures, conference HCII24

The collaboration in co-located shared environments has sparked an increased interest in immersive technologies, including Augmented Reality (AR). Since research in this field has primarily focused on individual user experiences in AR, the collaborative aspects within shared AR spaces remain less explored, and fewer studies can provide guidelines for designing this type of experience. This article investigates how the user experience in a collaborative shared AR space is affected by divergent perceptions of virtual objects and the effects of positional synchrony and avatars. For this purpose, we developed an AR app and used two distinct experimental conditions to study the influencing factors. Forty-eight participants, organized into 24 pairs, participated in the experiment and jointly interacted with shared virtual objects. Results indicate that divergent perceptions of virtual objects did not directly influence communication and collaboration dynamics. Conversely, positional synchrony emerged as a critical factor, significantly enhancing the quality of the collaborative experience. On the contrary, while not negligible, avatars played a relatively less pronounced role in influencing these dynamics. The findings can potentially offer valuable practical insights, guiding the development of future collaborative AR/VR environments., Comment: Paper accepted for publication/presentation at QoMEX 2024

Perturbation theory in asymptotically free quantum field theories is asymptotic. The factorially growing perturbative coefficients carry information about non-perturbative corrections, which can be related to renormalons and instantons. Using the Wiener-Hopf technique we determine the full analytic solution for the free energy density in the two dimensional $O(N)$ sigma models. For $N>3$ there are no instantons, and we found that the perturbative series carries all the information about the non-perturbative corrections. However, in the $O(3)$ case, we identify several non-perturbative sectors that are not related to the asymptotics of the perturbative series. The number of sectors depends on the observables: for the ground-state energy density we identify three sectors, which we attribute to instantons. For the free energy density in the running perturbative coupling we found infinitely many sectors., Comment: 76 pages, 7 figures

Given that experience is a pivotal dimension of learning processes in the field of leadership, the ongoing and unresolved issue is how such experiential moments could be provided when developing leadership skills and competencies. Role-plays and business simulations are widely used in this context as they are said to teach relevant social leadership skills, like those required by everyday communication to followers, by decision-making on compensation, evaluating performance, dealing with conflicts, or terminating contracts. However, the effectiveness of simulations can highly vary depending on the counterpart's ability to act in the given scenarios. In our project, we deal with how immersive media could create experiential learning based on simulations for leadership development. In recent years different variations of extended reality got significant technological improvements. Head-mounted displays are an easy and cost-efficient way to present high-resolution virtual environments. For groups of people that are part of an immersive experience, cave automatic virtual environments offer an excellent trade-off between actual exchange with other humans and interaction with virtual content simultaneously. The work presented is based on developing a user-centered simulation of leadership situations for cave automatic virtual environments and includes the results of a first usability study. In the future, the presented results can help to support the development and evaluation of simulated situations for cave automatic virtual environments with an emphasis on leadership-related scenarios.

Identification within media, whether with real or fictional characters, significantly impacts users, shaping their behavior and enriching their social and emotional experiences. Immersive media, like video games, utilize virtual entities such as agents, avatars, or NPCs to connect users with virtual worlds, fostering a heightened sense of immersion and identification. However, challenges arise in visually representing these entities, with design decisions crucial for enhancing user interaction. Recent research highlights the potential of user-defined design, or customization, which goes beyond mere visual resemblance to the user. Understanding how identification with virtual avatars influences user experiences, especially in psychological interventions, is pivotal. In a study exploring this, 22 participants created virtual agents either similar or dissimilar to themselves, which then addressed their dysfunctional thoughts. Results indicate that similarity between users and virtual agents not only boosts identification but also positively impacts emotions and motivation, enhancing interest and enjoyment. This study sheds light on the significance of customization and identification, particularly in computer-assisted therapy tools, underscoring the importance of visual design for optimizing user experiences.

Nowadays, Augmented Reality (AR) is available on almost all smartphones creating some exciting interaction opportunities but also challenges. For example, already after the famous AR app Pokemon GO was released in July 2016, numerous accidents related to the use of the app were reported by users. At the same time, the spread of AR can be noticed in the tourism industry, enabling tourists to explore their surroundings in new ways but also exposing them to safety issues. This preliminary study explores users' sense of safety when manipulating the amount and UI elements visualization parameters of Point of Interest (POI) markers in a developed AR application. The results show that the amount of POI markers that are displayed is significant for participants' sense of safety. The influence of manipulating UI elements in terms of transparency, color, and size cannot be proven. Nevertheless, most tested people stated that manipulating transparency and size somehow influences their sense of safety, so a closer look at them should be taken in future studies.

We revisit the problem of integrability breaking in free fermionic quantum spin chains. We investigate the so-called adiabatic gauge potential (AGP), which was recently proposed as an accurate probe of quantum chaos. We also study the so-called weak integrability breaking, which occurs if the dynamical effects of the perturbation do not appear at leading order in the perturbing parameter. A recent statement in the literature claimed that integrability breaking should generally lead to an exponential growth of the AGP norm with respect to the volume. However, afterwards it was found that weak integrability breaking is a counter-example, leading to a cross-over between polynomial and exponential growth. Here we show that in free fermionic systems the AGP norm always grows polynomially, if the perturbation is local with respect to the fermions, even if the perturbation strongly breaks integrability. As a by-product of our computations we also find, that in free fermionic spin chains there are operators which weakly break integrability, but which are not associated with known long range deformations., Comment: 26 pages, 6 figures, v2: references added, minor modifications

Two-dimensional (2D) materials combine many fascinating properties that make them more interesting than their three-dimensional counterparts for a variety of applications. For example, 2D materials exhibit stronger electron-phonon and electron-hole interactions, and their energy gaps and effective carrier masses can be easily tuned. Surprisingly, published band gaps of several 2D materials obtained with the $GW$ approach, the state-of-the-art in electronic-structure calculations, are quite scattered. The details of these calculations, such as the underlying geometry, the starting point, the inclusion of spin-orbit coupling, and the treatment of the Coulomb potential can critically determine how accurate the results are. Taking monolayer MoS$_2$ as a representative material, we employ the linearized augmented planewave + local orbital method to systematically investigate how all these aspects affect the quality of $G_0W_0$ calculations, and also provide a summary of literature data. We conclude that the best overall agreement with experiments and coupled-cluster calculations is found for $G_0W_0$ results with HSE06 as a starting point including spin-orbit coupling, a truncated Coulomb potential, and an analytical treatment of the singularity at $q=0$., Comment: This version of the article has been accepted for publication, after peer review but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1038/s41524-024-01253-2

A new method is presented that allows for efficient evaluation of spin-orbit coupling (SOC) in density-functional theory calculations. In the so-called second-variational scheme, where Kohn-Sham functions obtained in a scalar-relativistic calculation are employed as a new basis for the spin-orbit-coupled problem, we introduce a rich set of local orbitals as additional basis functions. Also relativistic local orbitals can be used. The method is implemented in the all-electron full-potential code \exciting. We show that, for materials with strong SOC effects, this approach can reduce the overall basis-set size and thus computational costs tremendously.

We develop a new method to calculate finite size corrections for form factors in two-dimensional integrable quantum field theories. We extract these corrections from the excited state expectation value of bilocal operators in the limit when the operators are far apart. We elaborate the finite size effects explicitly up to the 3rd L\"uscher order and conjecture the structure of the general form. We also fully recover the explicitly known massive fermion finite volume form factors., Comment: 39 pages, 9 figures. In this corrected manuscript, we clarified the text at multiple points and added a separate section (5) containing the definition of the connected form factors and a derivation of the graph rules for their evaluation. We also added a short section (6) about how our calculation can be extended from a one-particle state to multiparticle states

Whitin Istituto Nazionale di Fisica Nucleare (INFN) outreach activities, the Lab2Go project is of great significance. Its goal is involving high school teachers and students in several laboratory activities, aiming at increasing the weight of experimental contents in teaching and learning. In this article we present the measurement, carried out in the framework of the Lab2Go project, of the cosmic muon flux made by an ArduSiPM-based muon telescope.

We analyze a family of generalized energy densities in integrable quantum field theories in the presence of an external field coupled to a conserved charge. By using the Wiener-Hopf technique to solve the linear thermodynamic Bethe ansatz equations we derive the full analytic trans-series for these observables in terms of a perturbatively defined basis. We show how to calculate these basis elements to high orders analytically and reveal their complete resurgence structure. We demonstrate that the physical value of the generalized energy densities is obtained by the median resummation of their ambiguity-free trans-series., Comment: 13 pages, 1 figure, v2: minor additions