Seminare

Development of quantum hardware and software is progressing rapidly. With the availability of first generally-accessible quantum computers, their potential use for applications can increasingly be explored. One prospective field of application is data science in the medical sector, which faces challenges difficult to address with currently available methods. An example is medical imaging, where frequently only limited training data is available – making the use of classical AI methods difficult. However, presently available quantum computers are still limited in the number of qubits, the connectivity and are affected by noise. [mehr]

I will review my recent progresses in high harmonic generation in semiconductors, stepping from its classical nature to the recent evidence of its non-classical properties. [mehr]

The pseudogap is mysterious metallic state of electrons which appears above the critical temperature of correlated electron superconductors, most prominently in the lightly-hole-doped cuprates. I argue that the pseudogap is best understood as the finite temperature realization of a metallic ground state with a spin liquid character, andpresent a theory using a bi-layer of ancilla qubits. This theory leads to a variational wavefunction for the pseudogap state, to gauge theories for transitions and crossovers out of the pseudogap, and to a unifying perspective on the cuprate phase diagram. [mehr]

The investigation of ultrafast processes initiated in molecules by light absorption is of crucial importance in various research areas, from molecular physics to material science, from chemistry to biology. They are at the heart of emerging technological applications, where photo-induced electron transfer and charge transfer play a key role. In the last few years, the use of attosecond pulses has demonstrated to be a very powerful tool for the investigation of physical processes evolving in molecules on time scales ranging from a few femtoseconds down to tens of attoseconds. The introduction of new attosecond spectroscopic techniques, together with the development of sophisticated theoretical methods for the interpretation of the experimental outcomes, allowed unravelling and investigating physical processes never observed before. The application of attosecond methods to molecular physics has opened new research frontiers. Experimental advances, in terms of new sources, devices and techniques, are still required, together with new theoretical tools and approaches, but attosecond molecular physics has firmly established as a mature research field. [mehr]

Short attosecond (as) or few femtoseconds (fs) IR and UV pulses have a broad energy bandwidth which allows exciting a superposition of several electronic states in neutral molecules and molecular cations.[1] The nature of the states excited can be controlled by tuning the pulse parameters. This opens the way to novel avenues for control by engineering of electronic coherences between selected electronic states to steer charge migration on a purely electronic time scale.[2] As the nuclei begin to move, the electronic and nuclear motions are entangled and the engineered electronic coherences can be usefully exploited for directing the vibronic density through the network of non adiabatic interactions to specific products. [mehr]