Podcasts about luttinger

This month, we're pushing the limits of ideal models. A recent study in Nature Communications shows how the physics of 1D systems deviates from the model in unexpected ways when the temperature is raised. Tune in to find out more...Featuring Ruwan Senaratne (Rice University, USA) and Bishwanath Gaire (Nature Communications).Hosted by Ankita Anirban (Nature Reviews Physics) and Cristiano Matricardi (Nature communications)Ref: Cavazos-Cavazos, D., Senaratne, R., Kafle, A. et al. Thermal disruption of a Luttinger liquid. Nat Commun 14, 3154 (2023). https://doi.org/10.1038/s41467-023-38767-0 Hosted on Acast. See acast.com/privacy for more information.

Gauge/Gravity Duality 2013

The functional renormalization group (RG) is an ideal tool for dealing with the diversity of energy scales and competition of instabilities in interacting fermion systems. Starting point is an exact flow equation which yields the gradual evolution from a microscopic model action to the effective low-energy action as a function of a continuously decreasing energy scale. Expanding in powers of the fields yields an exact hierarchy of flow equations for vertex functions. Truncations of this hierarchy have led to powerful new approximation schemes [1]. Applications reviewed in the colloqium include: (i) d-wave superconductivity and other instabilities in the two-dimensional Hubbard model, and (ii) transport through a barrier and resonant tunneling in a one-dimensional Luttinger liquid metal. Recently, the functional RG has been upgraded from a weak-coupling method to a computational tool for strongly interacting fermion systems [2,3]. [1] W. Metzner et al., Rev. Mod. Phys. 84, 299 (2012). [2] C. Taranto et al., Phys. Rev. Lett. 112, 196402 (2014). [3] D. Vilardi et al., Phys. Rev. B 99, 104501 (2019).

A single potential impurity can drastically change a low-temperature transport of strongly interacting particles in one dimension - a sys- tem which is known as the Luttinger liquid. An arbitrary weak backscattering of fermions from the impurity totally destroys their zero-temperature current while even a very strong backscattering of bosons makes no impact on their flow. On the other hand, a more complicated impurity (like a quantum dot or a double-barrier struc- ture with a resonant level) can preserve an ideal resonant conductance of fermions, or conversely lead (in a different geometry) to an ideal (i.e. infinite) resonant resistance. I emphasize the role of a so-called duality in these transport effects. The duality was related to the integrability of the Luttinger liquid with an impurity. I will show that - surprisingly - duality survives the addition of a non-local and retarded interaction (like electron-phonon) which almost certainly destroys the integrability.

This thesis contributes to the field of nonequilibrium phenomena in many-body quantum systems. The properties of systems driven out of equilibrium are studied from three different perspectives: dynamics, thermodynamics, and dynamical phase transitions. The real-time dynamics of quenched quantum systems is studied on the basis of explicit examples of strongly-correlated many-body systems such as the Kondo model, the Luttinger liquid, and the anisotropic Heisenberg chain. The thermodynamic point of view is addressed in terms of the nonequilibrium work fluctuation theorems. In particular, it is shown that work distribution functions and thus also the Crooks relation can be measured in optical spectra of the x-ray edge type. The central aspect of this thesis is the definition of a dynamical phase transition for closed quantum many-body systems that is then analyzed in detail for the one-dimensional transverse field Ising model. In the end the properties of periodically driven quantum systems is discussed for different models such as the Kondo model, resonant level model, and the Luttinger liquid.

Abstract: In the presence of interactions, one-dimensional (1D) systems behave very differently from their higher-dimensional counterparts. Fermi liquid theory breaks down: the elementary excitations in 1D are not electron-like. Instead the 1D system is a so-called Tomonaga-Luttinger liquid with collective excitations. In experiment, signatures of one-dimensional (1D) behavior have, e.g., been observed in quantum wires and carbon nanotubes as well as cold atomic gases. While the 1D aspects make the above mentioned systems so fascinating, the real world is three-dimensional and, therefore, even in these confined geometries, features pertaining to deviations from one-dimensionality may remain. My interest is in identifying how the one-dimensional effects are modified in realistic situations and exploring the novel phenomena that arise. The colloquium will address the transition from a one-dimensional to a quasi-one-dimensional state of interacting electrons in a quantum wire as well as interesting spin properties in the quasi-one-dimensional regime. Julia S. Meyer, from The Ohio State University, visited the University of Arizona as a UA ADVANCE Junior Scientist Speaker and gave a 50- to 60-minute lecture on her research as part of the physics department lecture series. Philippe R. Jacquod, associate professor of physics, nominated her for the award. With the need to miniaturize electronic components below the nanoscale barrier, low-dimensional physics has come to play a central role in modern condensed matter physics and nanoscience. Meyer's research investigates the interplay between low dimensionality as well as interactions and disorder in nanoelectronic systems. These aspects are key to understanding how electricity is transmitted across such systems, a necessary step if one wants to include them as building blocks in nanoscale electronic circuits. Some of Meyer's more spectacular theoretical results include the construction of the phase diagram for interacting electrons in quantum wires, with the emergence of paramagnetic and (finite-sized) ferromagnetic phases, and the breakdown of Luttinger physics with the emergence of a single, fermionic gapless mode. September 11, 2009.

Lerner, I (Birmingham) Tuesday 16 September 2008, 14:00-15:00