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.

Extendemos la invitación a la comunidad del Instituto de Física y público interesado a participar de este coloquio.

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.

Extendemos la invitación a la comunidad del Instituto de Física y público interesado a participar de este coloquio.