Analog Quantum Chemistry Simulation with Ultra-cold Atoms


Analog Quantum Chemistry Simulation with Ultra-cold Atoms

Title: Analog Quantum Chemistry Simulation with Ultra-cold Atoms.
When: Friday, November 30, (2018), 12:00.
Place: Department of Theoretical Condensed Matter Physics, Faculty of Sciences, Module 5, Seminar Room (5th Floor).
Speaker: Alejandro Gonzalez Tudela, Institute of Fundamental Physics, CSIC, Madrid, Spain.

Solving quantum chemistry problems with a quantum computer is one of the most exciting applications of future quantum technologies. Current efforts are focused on finding on efficient algorithm that allow the efficient simulation of chemistry problems in a digital way. In this talk, I will present a complementary approach to the problem which consists in simulating quantum chemistry problems using ultra-cold atoms. I will first show how to simulate the different parts of the Hamiltonian, and then benchmark it with simple molecules.

References

  1. Unconventional quantum optics in topological waveguide QED, Miguel Bello, Gloria Platero, Juan Ignacio Cirac, Alejandro González-Tudela, arXiv:1811.04390, (2018).



Heavy, heavier, the softest - Heavy Electrons to Explore Correlated Quantum Matter


INC COLLOQUIUM – OFFICIAL ANNOUNCEMENT

Heavy, heavier, the softest - Heavy Electrons to Explore Correlated Quantum Matter

Title: Heavy, heavier, the softest – Heavy Electrons to Explore Correlated Quantum Matter.
When: 10 December, 2018, 12h30
Where: Sala de Conferencias, Módulo 00, Faculty of Sciences, UAM.
Speaker: Silke Paschen, Vienna University of Technology, Austria.

Electronic correlations are a central theme in contemporary condensed matter physics – and hold promise for new functionality in quantum materials. In this talk I will show that heavy fermion compounds are ideal model systems to explore quantum phases and fluctuations driven by correlations. The effective mass of the conduction electron in a heavy fermion metal is not only ‘heavy’, but can become heavier and heavier on driving the system towards a quantum critical point, where the mass may ultimately diverge. At this point, a critical continuum of excitations leads to exotic properties not captured by the standard theory of metals, Fermi liquid theory. The associated accumulation of entropy makes the material extremely soft to the formation of new phases, including unconventional forms of superconductivity.




Looking for Magnetism in Graphene


Looking for Magnetism in Graphene

Title: Looking for Magnetism in Graphene.
When: Tuesday, November 20, (2018), 12:00.
Place: Department of Theoretical Condensed Matter Physics, Faculty of Sciences, Module 5, Seminar Room (5th Floor).
Speaker: Felix Yndurain, Condensed Matter Physics Department, Universidad Autónoma de Madrid, Spain.

One of the most active research topics in graphene has been the search of magnetism.  In the recent past, and based on Lieb’s theorem [1], the research has been focused on point defects like vacancies or adsorbed single atoms like hydrogen or fluorine [2,3]. Very recently, the work of Prof. P. Jarillo-Herrero’s group at MIT [4] has opened the possibility of correlated states in defect’s free twisted graphene bilayers. These issues will be discussed in the talk along recent results on magnetic moments in twisted bilayers [5].

References

  1. E. H. Lieb, Phys. Rev. Lett. 62, 1201 (1989).
  2. H. González-Herrero et al. Science, 352,437 (2016).
  3. H. González-Herrero et al. To be published.
  4. Y. Cao et al. Nature (London) 556, 43 (2018).
  5. F. Yndurain. To be published



When Light Goes Small


INC COLLOQUIUM – OFFICIAL ANNOUNCEMENT

When Light Goes Small

Title: When Light Goes Small.
When: 19 November, 2018, 12h30
Where: Sala de Conferencias, Módulo 00, Faculty of Sciences, UAM.
Speaker: Javier Aizpurúa, Center for Materials Physics San Sebastián, DIPC, Spain.

Electronic excitations and vibrations of molecules can be efficiently excited by light thanks to the action of optical resonators which improve the interaction between light and matter. Plasmonic cavities emerge as a special type of optical resonators which “make light small ” giving rise to a reduction of the electromagnetic effective mode volume down to the nanoscale, as well as to a dramatic enhancement of the local near-fields.

This enhanced “small light” allows for bringing molecular spectroscopy such as fluorescence or Raman scattering to extreme levels of detection and manipulation, reaching the single-molecule regime. Furthermore, atomic-scale morphological features in plasmonic cavities produce the ultimate confinement of light, setting sub-nanometric access and control of single-molecule electronic excitations and nanoscale molecular optomechanics. To describe the interaction of light and matter at this extreme level, quantum theoretical frameworks need to be developed.




Universal Natural Shapes


Universal Natural Shapes

Title: Universal Natural Shapes.
When: Tuesday, November 13, (2018), 12:00.
Place: Department of Theoretical Condensed Matter Physics, Faculty of Sciences, Module 5, Seminar Room (5th Floor).
Speaker: Johan Gielis, University of Antwerp, The Antenna Company, Belgium.

In the natural sciences, global anisotropies or (quasi-) periodic local deviations from isotropy or Euclidean perfection in many forms that occur in nature can be effectively dealt with by applying Gielis transformations to the basic forms that show up in Euclidean geometry, e.g. circle and spiral. Since their introduction in botany in 2003, Gielis curves, surfaces and transformations have been used in various fields of science and technology, including in nanotechnology. I will focus on 1) further generalizations and Pythagorean-compact representations, 2) Applications in biology and antennas, and 3) Generalized Möbius-Listing surfaces and bodies, in the context of possible further applications in nanotechnology and nanophotonics.




An Operational Approach to Quantum Stochastic Thermodynamics


An Operational Approach to Quantum Stochastic Thermodynamics

Title: An Operational Approach to Quantum Stochastic Thermodynamics.
When: Monday, November 5, (2018), 12:00.
Place: Department of Theoretical Condensed Matter Physics, Faculty of Sciences, Module 5, Seminar Room (5th Floor).
Speaker: Philipp Strasberg, Universitat Autònoma de Barcelona, Spain.

Whenever a small, fluctuating system is continuously, passively and perfectly observed, classical stochastic thermodynamics provides a successful theory to describe its thermodynamics far from equilibrium. The problem that not even classically it is well understood how to include, e.g., disturbing or incomplete measurements, has also hindered progress in formulating a quantum version of the theory.

Based on the recently developed process tensor, which describes a quantum stochastic process with arbitrary experimental interventions (a quantum causal model), I will define internal energy, heat, work and entropy along a single trajectory. These definitions fulfill a first law at the trajectory level and a second law on average. As a guiding example throughout the talk, I will use the photon number stabilization experiments performed in the group of Serge Haroche.




PhD Position in Nanoscale Thermal Transport – Closed


PhD Position in Nanoscale Thermal Transport

Position type: PhD position in Theoretical Condensed Matter Physics (FPI fellowship).
Topic: Nanoscale thermal transport.
Duration: 4 years.
Principal Investigator: Juan Carlos Cuevas (http://webs.ftmc.uam.es/juancarlos.cuevas/).
Requirements: Graduate in Physics that have completed a Master in Condensed Matter Physics or related areas.
When to apply: from 8 to 29 October (2018).
How to apply: via sede electrónica del Ministerio Ciencia, Innovación y Universidades: https://sede.micinn.gob.es/portal/site/eSede/
Approximate starting date: February 2019.
For more info: contact me at juancarlos.cuevas@uam.es

Description of the project:

The general goal of this project is the theoretical study of several fundamental aspects of nanoscale thermal transport. In particular, we want to improve our current understanding of the radiative heat transfer and thermal radiation in nanoscale systems. We also want to elucidate the fundamental physical mechanisms that govern the heat conduction in atomic-scale junctions. Additionally, we intend to study the energy dissipation and, in particular, the thermoelectric cooling in molecular junctions. All these issues are of fundamental importance for many different fields and disciplines such as thermal sciences, nanoelectronics, nanooptics, and condensed matter physics. Moreover, these problems are key to developing novel technologies like near-field based thermal management, thermophotovoltaics, and nanoscale energy conversion.




Radiative Heat Transfer


Radiative Heat Transfer

Article: published in ACS Photonics by Juan Carlos Cuevas and Francisco J. García-Vidal, IFIMAC researchers and members of the Department of Theoretical Condensed Matter Physics.

Thermal radiation is one of the most ubiquitous physical phenomena, and its study has played a key role in the history of modern physics. The understanding of this subject has been traditionally based on Planck’s law, which in particular sets limits on the amount of thermal radiation that can be emitted or exchanged. However, recent advances in the field of radiative heat transfer have defied these limits, and a plethora of novel thermal phenomena have been discovered that in turn hold the promise to have an impact in technologies that make use of thermal radiation. Now, in an article published by ACS Photonics, the IFIMAC researchers Juan Carlos Cuevas and Francisco J. García-Vidal review the rapidly growing field of radiative heat transfer, paying special attention to the remaining challenges and identifying future research directions. In particular, they focus on the recent work on near-field radiative heat transfer, including (i) experimental advances, (ii) theoretical proposals to tune, actively control, and manage near-field thermal radiation, and (iii) potential applications. They also review the recent progress in the control of thermal emission of an object, with special emphasis in its implications for energy applications, and in the comprehension of far-field radiative heat transfer. Heat is becoming the new light, and its understanding is opening many new research lines with great potential for applications.

Reference:

  1. Radiative Heat Transfer, Juan Carlos Cuevas and Francisco J. García-Vidal, Published in ACS Photonics, September 19th (2018). DOI: 10.1021/acsphotonics.8b01031 [URL]

 




Non-perturbative Cavity QED


Non-perturbative Cavity QEDTitle: Non-perturbative Cavity QED.
When: Thursday, September 27, (2018), 11:00.
Place: Department of Theoretical Condensed Matter Physics, Faculty of Sciences, Module 5, Seminar Room (5th Floor).
Speaker: Peter Rabl, Vienna University of Technology, Austria.

In quantum optical systems the coupling between a single dipole and a single cavity mode is always much smaller than the absolute energy scales involved, which allows us to understand and model light-matter interactions in terms of well-defined atomic and photonic excitations. With recent advances in the field of circuit QED it is now possible to go beyond this well-established paradigm and enter a fully non-perturbative regime, where the coupling between a single artificial atom (e.g. a superconducting qubit) and a microwave photon exceeds the energy of the photon itself. Such conditions can be associated with an effective finestructure constant of order unity and in this talk I will give a brief introduction about the basics models and novel effects that govern the physics of light-matter interactions in this previously unaccessible regime.




Lightwave Driven Quantum Dynamics: from molecular movies to Bloch waves


INC COLLOQUIUM – OFFICIAL ANNOUNCEMENT

Lightwave Driven Quantum Dynamics: from molecular movies to Bloch wavesTitle: Lightwave Driven Quantum Dynamics: from molecular movies to Bloch waves.
When: 17 September, 2018, 12h30
Where: Sala de Conferencias, Módulo 00, Faculty of Sciences, UAM.
Speaker: Jens Biegert, ICFO – The Institute of Photonic Sciences, Barcelona – Spain.

Electron recollision in an intense laser field gives rise to a variety of phenomena, ranging from electron diffraction to coherent soft X-ray emission. We have, over the years, developed intense sources of waveform-controlled mid-IR light to exploit the process with respect to ponderomotive scaling, quantum diffusion and quasi-static photoemission. I will describe how we leverage these aspects to “teach” molecules to take a selfie while undergoing structural change. This permits visualizing for the first time, with combined attosecond temporal and atomic spatial resolution, molecular bond breaking and deprotonation. Furthermore, we achieve isolated attosecond pulses in the soft X-ray water window across the oxygen edge at 534 eV. Accomplishing ultrafast temporal resolution in combination with the soft X-ray’s element specificity now provides an entirely new view on the combined electronic and nuclear dynamics in real time. I will show first results in which we resolve the carrier dynamics in a quantum material in real time and within the material’s unit cell.
These results provide first comprehensive insight into the dynamics of molecules and condensed matter, with the future possibility to address fundamental and long-standing questions such as molecular isomerization, phase transitions and superconductivity.

Lightwave Driven Quantum Dynamics: from molecular movies to Bloch waves