Analytical models describing a colloidal particle confined in a harmonic well, e.g. provided by an optical trap, and driven by shear flows are presented. Violation of both static and dynamic fluctuation-dissipation theorem (FDT) is clearly seen, thus clarifyingthe connection between such FDT violation and the breakdown of the detailed balance. The simple shear and Taylor-Couette velocity fields are studied in detail, showing that loosening confinement enhances FDT violations. In addition, cases violatingFDT but not energy equipartition are presented. For the cases under study, an effective temperature is defined via the static FDT, which appears to be more physically sound than the one defined via the time-dependent FDT. Confining sheared colloidal particles by optical tweezers yields considerable FDT violation.
Violation of the Fluctuation-Dissipation Theorem in Confined Driven Colloids
MAURI, ROBERTO;LEPORINI, DINO
2006-01-01
Abstract
Analytical models describing a colloidal particle confined in a harmonic well, e.g. provided by an optical trap, and driven by shear flows are presented. Violation of both static and dynamic fluctuation-dissipation theorem (FDT) is clearly seen, thus clarifyingthe connection between such FDT violation and the breakdown of the detailed balance. The simple shear and Taylor-Couette velocity fields are studied in detail, showing that loosening confinement enhances FDT violations. In addition, cases violatingFDT but not energy equipartition are presented. For the cases under study, an effective temperature is defined via the static FDT, which appears to be more physically sound than the one defined via the time-dependent FDT. Confining sheared colloidal particles by optical tweezers yields considerable FDT violation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
