Portal del coneixement obert de la UPC

Enviaments recents

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  Article Accés obert

  Probing supersolidity through excitations in a spin-orbit-coupled Bose-Einstein condensate

  (Science, 2026-01-29) Chisholm, Craig; Hirthe, Sarah; Makhalov, Vasiliy; Ramos, Ramón; Vatre, Remy; Cabedo, J; Celi, A; Tarruell, Leticia

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  Spin-orbit-coupled Bose-Einstein condensates are a flexible experimental platform to engineer synthetic quantum many-body systems. In particular, they host the so-called stripe phase, an instance of a supersolid state of matter. The peculiar excitation spectrum of the stripe phase, a definite footprint of its supersolidity, has been difficult to measure experimentally. In this work, we performed in situ imaging of the stripes and directly observed both superfluid and crystal excitations. We investigated superfluid hydrodynamics and revealed a stripe compression mode, thus demonstrating that the system possesses a compressible crystalline structure. Through the frequency softening of this mode, we located the supersolid transition point. Our results establish spin-orbit-coupled supersolids as ideal systems to investigate supersolidity and its rich dynamics.

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  Treball Final de Grau Embargat per acord de confidencialitat (2031-07-01)

  Simulator for the stratosens project: Trajectory and imagery generation, and ground processing chain for a HAPS payload

  (Universitat Politècnica de Catalunya, 2026-07-02) Fernández Falcó, Joan Lluc; Airbus Defence and Space; Universitat Politècnica de Catalunya. Departament d'Enginyeria Electrònica

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  This bachelor's thesis pursues two objectives, both developed for the STRATOSENS project in collaboration with Airbus GeoTech: a training simulation environment for the HAPS payload, and a GPU-accelerated ground image processing pipeline. Together they let the payload software and the ground segment be developed and validated on the bench, without flying the HAPS or exercising the real flight hardware. The simulation environment synthesises aerial imagery from the aircraft pose, projecting georeferenced basemap and terrain data into the sensor perspective view, and streams INS-GNSS navigation telemetry to the OBC in the same NMEA-0183 format as the real unit. The synthetic frames are delivered to the ground over the same real datalink as the payload, so the ground segment receives imagery exactly as it would in flight. This lets simulated operations run alongside the real OBC while remaining transparent to the ground segment. This thesis covers the full design of the training simulator, including the synthetic image generation pipeline, the HAPS trajectory generator, and the real-time telemetry and image delivery path. It also presents the design and implementation of the architecture and functions of the GPU-accelerated ground image processing pipeline that decompresses, post-processes, and georeferences the received imagery, together with the integration and validation of the complete system.

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  Apunts Accés obert

  Àlgebra multilineal i geometria

  (Universitat Politècnica de Catalunya, 2023-02) Planas Vilanova, Francesc d'Assís

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  Apunts Accés obert

  Corbes algebraiques, segons W. Fulton

  (Universitat Politècnica de Catalunya, 2020-05) Planas Vilanova, Francesc d'Assís

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  Treball Final de Grau Accés obert

  Aerodynamic performance of airfoils with non-smooth surfaces

  (Universitat Politècnica de Catalunya, 2026-06-30) Garcia Cáceres, Mònica; Universitat Politècnica de Catalunya. Departament de Física

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  Passive flow control aims to improve aerodynamic performance through surface modifications without requiring external energy. In this thesis, the aerodynamic behaviour of a three dimensional NACA 2412 airfoil at an angle of attack of 15º is investigated using Computational Fluid Dynamics (CFD) simulations in ANSYS Fluent. The objective is to evaluate whether dimple modifications on the upper surface can improve aerodynamic performance by delaying boundary layer separation. A baseline airfoil configuration is first analysed and used as a reference case. Several dimple configurations are then evaluated by varying both their chordwise location and geometric distribution. A mesh independence study is performed, and the same numerical setup is maintained for all simulations to ensure a consistent comparison between cases. The results indicate that the dimples modify the local flow field and generate recirculation regions inside the cavities, but these effects do not translate into a significant overall aerodynamic improvement compared with the baseline airfoil. The best aerodynamic performance is obtained for the Single Dimple configuration located at 60% of the chord, which produces a slightly higher lift coefficient than the reference case. In contrast, the Double Dimple configuration at 60% of the chord exhibits the lowest aerodynamic efficiency among the configurations considered. From the perspective of boundary layer separation, the most favourable result is achieved by the Trefoil configuration at 70% of the chord, which delays the separation point from 82% of the chord in the baseline case to 86.7% of the chord. However, this delay does not lead to a significant increase in lift or aerodynamic efficiency. Overall, the studied dimple geometries do not provide sufficiently large performance improvement to justify their selection as an effective passive flow control solution under the simulated conditions. Nevertheless, the results suggest that further investigations using finer mesh resolutions around the dimples may be worthwhile.

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