• Disorder and rare eventsDisorder and rare events completely change the behavior of magnetic systems close to a quantum critical point, leading to quantum Griffiths phases.

• In metallic magnets additional long-ranged RKKY interactions couple the rare regions causing non-Ohmic dissipation.

• In electronic Griffiths phases: (disordered heavy fermions far from magnetic ordering) this leads to disorder-induced fractionalization and spin liquid behavior (D. Tanaskovic, V. Dobrosavljevic, and E. Miranda, Phys. Rev. Lett. 2005, in press).

• In magnetic Griffiths phases: RKKY interactions lead to dissipative freezing of magnetic droplets and the formation of cluster-glass phases (V. Dobrosavljevic and E. Miranda, Phys. Rev. Lett. 94, 187203 (2005)).

• Both mechanism can lead to disorder-driven non-Fermi liquid behavior. Recent review: E. Miranda and E. Miranda and V. Dobrosavljevic, Reports on Progress in Physics 68, 1-72 V. Dobrosavljevic, Reports on Progress in Physics 68, 1-72 (2005) .(2005) .

RKKY Interactions and Dissipation in Metallic Griffiths PhasesRKKY Interactions and Dissipation in Metallic Griffiths Phases Vladimir Dobrosavljevic, Florida State University, DMR-0234215Vladimir Dobrosavljevic, Florida State University, DMR-0234215

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Griffiths droplets

RKKY interactions mediating non-Ohmic dissipation in magnetic Griffiths phases (top). Phase diagram of the induced cluster-glass phase (bottom).

Outreach activities:

• The PI presented a “Saturday Morning Physics” lecture “Physics on the Web” to High School students.

• The PI participated in the Florida State University Physics Department Open House, with a display: “Physics of Paper Airplanes for Kids”.

• The PI participated in the NHMFL Annual Open House activities with a display “Physics of Behind Magnetism”).

Educational:

One undergraduate student, two graduate students and a postdoc contributed to these projects. These students received training in many-body theory, including computer modeling and analytical calculations.

Synergistic Activities: the PI, together with E. Dagotto, S. Sachdev, and J. Zaanen organized an international workshop at the Lorentz Center (Leiden, The Netherlands) that drew roughly 60 international participants.

RKKY Interactions and Dissipation in Metallic Griffiths PhasesRKKY Interactions and Dissipation in Metallic Griffiths Phases Vladimir Dobrosavljevic, Florida State University, DMR-0234215Vladimir Dobrosavljevic, Florida State University, DMR-0234215