Flash Presentations for posters

These were ~2min presentations to advertise posters, which will hang in the upstairs hallway this week.

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Igor Burmistrov
"Enhancement of superconductivity Anderson Localization"
RG treatment of disordeed lecterns with short range interactions. They find a a strong enhancement of Tc for 2D system short ranged interactions in the intermediate range of disorder regime. They also find a strong enhancement of Tc near Anderson transition with short range interations . The enhancement of Tc is due to multifactaility of electron wave functions. This work can be found at arxiv/1102.3323

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Pieter-Jan Coumou
"Electrodynamic response of strongly disordered superconducting TiN films"
They make modifications to Matthis-Bardeen (MB) formalism to fit microwave strip line resonator data. In-gap states which presumably come from disorder can explain the deviation to MB.

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Eduard Driessen
"The Superconducting Transition HIghlty Resistive NbTiN Nanowires"
They are interested in how disorder and electronic segregation influence the resistance transition of nanowires? They find step resistance of 5-10Kohm in I-V curves. Interestingly the critical current data shows evidence of higher Tc than R vs. T curves. This has been interpreted in terms of "pre-formed pairs" above the actual thermodynamic transition.

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Shawna Hollen,
"Cooper Pair Islanding in Amorphous Thin Films"
They do Bi film deposition of a substrate with holes in it and see oscillations consistent with 2e particles on insulating side of SIT. Bi films on holey substrate shows exponential activation, whereas Bi on glass shows ln(T) behavior. They also see giant magnetoresistance peak. A recent study shows that there is a thickness variations in their deposited films and the blogger believes they are implying that this may impose some sort of granularity on this system.

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Alina Hriscu
"Phase-slip devices"
They have made proposals for detection of coherent quantum phase-slips through different device geometries.

3 different devices.
1.) Phase slip oscillator
2.) Quantum phase slip box
3.) Quantum phase slip transistor
Work can be found in PRB 83 2011

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Andrew "Jamie" Kerman
"A Theory for Quatnum Phase-Slips in 1D Superconductors Based on Flux-Charge Duality"
Theory based on picture of Mooij and Nazarov of Charge-Flux Duality. Tunneling of Phase-slip events from insulator through superconductor.

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Madhavi Chand
"Phase Fluctuations in NbN films"
NbN thin films allow disorder to be tuned over wide range by varying sputtering parameters. In tunneling data they observer a pseudogap at high temperatures above Tc. High Disorder samples have a magnetoresistance peak (but which is slightly smaller than other samples). The magnetoresistance peak disappears close to T*. They present phase diagram for disorder in 3D films, which has a significant PG regime that runs into Tc at low disorder.

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Markus Mueller
"Giant magnetoresistance and localization in boxonic insulators"
Markus has written down a theory for hopping hard core bosons (preformed pairs) in a tight-binding mode and ask what is amplitude for boson to proposage from one lattice state to another.

Bosons are different than fermions. Bosons amplitudes for different paths have same sign. Fermions have different signs. This means that Bosons delcoalize more than fermions in equal disorder. Fermions have negative magnetoresitance, while Bosons have positive magnetoresistance naturally in this model.

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Konstantin Tikhonov
"Superconducting fluctuations apron h with non-linear sigma model"
Generalize T and H regimes for superconducting fluctuations and can calculate Hall effect. Use Kelydesh formalism to calculate supercocnducting fluctuations in non-equilbrium conditions.