The radiative heat transfer, existing between any couple of bodies at different temperatures in vacuum, is limited in the far field by the well-known Stefan Boltzmann's law.

In the near field (for distances smaller than the thermal wavelength) it can overcome by orders of magnitude this limit, especially in the presence of resonant surface modes. In the first part of the talk, we address the heat transfer between two nanoparticles in the proximity of a planar substrate, and show how the presence of a surface mode supported by the substrate can amplify even by two orders of magnitude the interparticle flux.

In the second part of the talk, we discuss the thermomechanical behavior of a bimaterial cantilever which exchanges heat flux radiatively in the near field with a substrate. We show that such a system can support bistability, i.e. the existence of more than one stable solution for the temperature and the displacement profile. This could pave the way to a possible boolean treatment of information from heat flux at microscale.

Spin-waves, or their quantized counterparts (magnons) are propagating waves formed by the collective spin excitations in a magnetic body. In standard magnetic thin films and devices, spin-waves have typically frequencies in the 1-50 GHz range and wavelengths from 10 nm to 10 µm. As spin-waves determine to a large extent the rate at which one can manipulate the magnetization, they are of central importance in various applications of spin electronics, e.g. solid state magnetic memories, microwave magnetic oscillators and magnetization-based rf devices.
In this seminar, I shall start with an introduction to spin-wave dynamics, spin-wave spectroscopy, and the potential applications thereof. While the generation, detection, propagation and phase manipulation of spin-waves in spintronics devices is now well understood, the implementation of magnon-based computing or spin-wave based manipulation of information requires now to design energy-efficient spin wave transceivers. I will review our effort on inductive transceivers, and detail how we can harness them to fabricate a micrometer-scale spin wave majority gate with frequency multiplexing capability. I will then describe our efforts in the search of more efficient spin-wave transceivers. This includes spin-transfer-torque emitters, as well as the coupling of spin-waves to acoustical waves.

Shampoos, lubricants, and other complex fluids display a viscoelastic behavior due to the wormlike micellar networks formed by their surfactants. These networks are an instance of "living polymers", a name recalling the continuous breaking and rejoining of the tubular structures formed by the surfactants.

With a a novel coarse-grained model of complex soft matter networks, we show that they can experience a transient equilibration much longer than their local rearrangements. Our large-scale simulations unveil bottlenecks in the local dynamics that lead to the stagnant global equilibration. In agreement with experimental data, timescales for the thermal activation of single scission events of the network strands may be found up to millisceconds. Yet, the need of overcoming topological constraints through a sequence of intermediate unfavorable structures (dangling ends and eventually branches) originates a slower (power-law) global relaxation of the system, which ends after time scales of seconds. This nontrivial time scales should be considered for estimating the Weissenberg and Deborah numbers in experiments of viscoelastic media.

In this talk, I am going to review some aspects of the current state of the art of Integrability in the AdS/CFT correspondence and beyond. I will first describe a general nonperturbative approach to compute correlation functions of local operators in the N=4 Supersymmetric Yang-Mills theory which allows us to explore the theory even beyond the most well studied planar limit. In the second part, I will describe my recent work about exploring deformations of N=4 Supersymmetric Yang-Mills by irrelevant operators, which revives an old attempt of generalizing the AdS/CFT correspondence. Here integrability seems to also play an important role and opens the door for its application for non-conformal field theories.

I'll give an introduction to the theory of mock modular functions and present recent results on modular behavior of indefinite theta series.

I'll continue the introduction to the theory of mock modular functions and indefinite theta series.

Quantum units from the topological engineering of molecular graphenoids

I will discuss the dynamics of a self-phoretic swimmer (self-propelled active colloid) near a solid wall. The self-phoretic swimmer, endowed with catalyst coating on its surface, self-propels in a viscous fluid by locally sustaining either a chemical concentration gradient (diffusiophoretic), electric field (electrophoretic) or both. The wall modifies the flow field, chemical concentration and the electric potential field gradients, leading to nontrivial behaviour of the swimmer. Using perturbation techniques and the method of images, I will present the isolated effects of the concentration and electric potential fields distortion on the swimmer dynamics, due to the wall. I will then show that the chemical concentration field distortion could be the dominant effect on the dynamics, not the long-range hydrodynamic flow field, and may lead to stable motion parallel to the wall at a fixed height and orientation.