El próximo jueves 2 de julio, el Dr. Felipe Barra, destacado investigador en Termodinámica Cuántica y profesor asociado de la Universidad de Chile, dictará el coloquio “Quantum Thermodynamics and Information: Maxwell’s Demon in a Quantum Thermoelectric Engine” a las 14:30 horas en la Sala 208 del Instituto de Física, Edificio de Ciencias, Campus Curauma, PUCV.

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Can information drive a current against a bias? This talk introduces a quantum thermoelectric engine where part of the system acts as an autonomous Maxwell’s demon.

The laws of thermodynamics are deeply connected with notions of information. Quantum thermodynamics explores this connection in systems where coherence, entanglement, and measurement backaction can affect energy and particle transport. In this talk, I will introduce some central ideas of the field through a concrete example: a multipartite quantum system operating as a thermoelectric engine. The device can be interpreted as an autonomous Maxwell’s demon, where one part of the system monitors another and helps drive a particle current against a chemical-potential bias. I will discuss how quantum coherences and correlations appear in the steady state, and how coupling to a dephasing environment induces a transition toward a more classical transport regime.

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El próximo jueves 25 de junio, la Dra. Paula Mellado, física teórica y profesora en la Universidad Adolfo Ibáñez (Santiago, Chile) dictará el coloquio “Sliding phasons in Moiré Ladders” a las 14:30 horas en la Sala 208 del Instituto de Física, Edificio de Ciencias, Campus Curauma, PUCV.

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An incommensurate charge density wave is a periodic modulation of charge that breaks trans-lational symmetry at a momentum that does not coincide with the primitive lattice vectors. Its Goldstone excitation, the phason, comprises collective gapless phase fluctuations. Aiming to unveil the mechanism behind the onset of incommensurate charge order in layered materials, we study a half-filled, four-band tight-binding model on a ladder with a relative shift δ = p/q between the legs, induced by the dimerization of one of them. The shift results in a moiré supercell comprising q composite cells and a modulated inter-leg tunneling. The moiré potential compresses the leg bands
into flat minibands near the Fermi level, resulting in additional low-energy peaks in the density of states. Including Coulomb interactions, we find an incommensurate charge-density-wave phase in which the charge modulation is out of phase between the legs. The collective excitations of this state are long-lived neutral, acoustic phasons whose speed is controlled by the moiré parameter δ and the inter-leg tunneling amplitude. This model sheds light on the role of interlayer incongruities in the formation of excitonic charge-ordered phases in van der Waals and heterostructured materials.

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El próximo miércoles 10 de junio, la Dra. Jo Dunkley, cosmóloga y profesora Joseph Henry de Física y Ciencias Astrofísicas en la Universidad de Princeton, dictará el coloquio “The Simons Observatory” a las 11 horas en la Sala 208 del Instituto de Física, Edificio de Ciencias, Campus Curauma, PUCV.

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The Simons Observatory (SO), a new millimeter-wave observatory in the Atacama, has started gathering data. It measures the cosmic microwave background (CMB), the earliest image we have of the universe, with the goal of better understanding our cosmological model. With its smaller telescopes we are seeking a primordial signal imprinted by gravitational waves generated in the early universe. Its largest telescope will measure the finer scales of the CMB with increased sensitivity, probing the initial conditions of the early universe as well as revealing the later-formed cosmic web of gas and dark matter.  By surveying half the sky every couple of days, we also hope to see new types of transient astronomical events in millimeter-wavelengths with SO. In this talk I will describe the status of SO and its science plans.

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El próximo miércoles 27 de mayo, el Dr. Gonzalo Palma, cosmólogo teórico y académico de la Universidad de Chile, dictará el coloquio “From the Wavefunction of the Universe to In-In-Correlators: A Perturbative Map to All Orders” a las 11 horas en la Sala 208 del Instituto de Física, Edificio de Ciencias, Campus Curauma, PUCV.

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In this talk, I will review recent progress in the systematic computation of primordial correlation functions. These quantities are central theoretical tools for connecting models of the early universe with cosmological observations. Two complementary frameworks play a key role in this problem: the Wavefunction of the Universe approach and the Schwinger-Keldysh, or in-in, formalism. Both are designed to describe the same physical observables, but they organize computations in rather different ways. Although their conceptual equivalence has long been appreciated, the precise relation between their diagrammatic expansions has remained somewhat obscure. I will describe a recent construction that makes this relation explicit. The result provides a clearer understanding of how different perturbative approaches to primordial cosmology are connected, and offers a useful perspective on the structure of cosmological observables.

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El próximo miércoles 06 de mayo, la Dra. Sapna Mishra, académica del Space Telescope Science Institute (Baltimore, Maryland, USA), dictará el coloquio “The Halos of Satellite Galaxies: Where Do Their Gas and Metals Go?” a las 11 horas en la Sala 208 del Instituto de Física, Edificio de Ciencias, Campus Curauma, PUCV.

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Satellite galaxies play a key role in the chemical evolution of the universe by redistributing gas and metals across halo environments. Their interactions with massive hosts through tidal and ram-pressure stripping regulate both their star-formation histories and the metal budget of their circumgalactic media (CGM). Yet, the diffuse CGM of satellite galaxies remains largely unexplored observationally. The Large Magellanic Cloud (LMC) provides the only well-characterized case to date. Our recent UV absorption-line studies with Hubble Space Telescope (HST) toward 28 background quasars reveal that the LMC’s metal-enriched CGM is truncated to one-tenth of its virial radius, consistent with ram-pressure stripping by the Milky Way’s hot corona. This provides a rare, direct view of how environmental forces remove or redistribute metals in low-mass galaxies. However, future UV observations are needed to explore how typical the MW-LMC interaction is, and how satellites retain their gas and metals? This presentation will highlight how HST will uniquely trace metals in other satellite CGMs across the Local Group and beyond.

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 El próximo miércoles 29 de abril, Claudia Scóccola, académica de la Universidad de Chile y destacada cosmóloga especializada en el Fondo Cósmico de Microondas (CMB por sus siglas en inglés), dictará el coloquio “Challenges and open directions in CMB B-mode data analysis” a las 11 horas en la Sala 208 del Instituto de Física, Edificio de Ciencias, Campus Curauma, PUCV.

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The search for primordial B-mode polarization in the Cosmic Microwave Background (CMB) is still one of the main problems in observational cosmology. Even with the significant progress of recent years, extracting robust cosmological information from current and upcoming data remains far from straightforward. In this talk, I will discuss some of the key challenges that shape current CMB B-mode analyses and how they affect the interpretation of the data. I will also comment on a few open directions that are currently being explored, with the goal of improving how we extract information from these observations.

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