5 Maggio 2014- Seminario di Dipartimento - Tony Shiroka - One-dimensional spin systems: A laboratory for complex quantum matter

Relatore: Tony Shiroka -

Laboratorium fur Festkorperphysik, ETH Zurigo, Switzerland and

Paul Scherrer Institut, Villigen PSI, Switzerland

Luogo: Aula Newton - Plesso Fisico

E-mail organizzatore: raffaella.burioni@fis.unipr.it

Abstract:

Abstract: Low-dimensional spin systems serve as simple models of magnetism, yet able

to demonstrate a broad spectrum of complex quantum physics: collective

excitations, quantum phase transitions, geometric frustration,

confinement, and asymptotic freedom. Recent breakthroughs in material

synthesis, including high-quality crystals, control of disorder, a shift

from oxides to halogenides, as well as advances in theory and

computational methods, have increased the interest and given new life to

the field.

The key advantage of investigating strong-correlation phenomena in spin

systems arises from the possibility of tuning the Hamiltonian via an

applied field, via pressure, or through chemical substitution, while still

being able to use well established techniques, such as magnetic resonance

or neutron scattering, sensitive to magnetism in real- and

reciprocal-space, respectively.

By the joint use of experimental and numerical techniques we will

illustrate the impact of frustration and disorder in some paradigmatic

one-dimensional compounds, where these ìperturbationsî give rise to rich

and largely unexplored phase diagrams, reflecting the interplay of quantum

and thermal fluctuations.