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VERSION:2.0
PRODID:-//Memento EPFL//
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SUMMARY:QSE Quantum Seminar: "Anomalous Frequency Shift in Low-Loss Superc
 onducting Granular Aluminum Resonators"
DTSTART:20260730T123000
DTEND:20260730T140000
DTSTAMP:20260922T022113Z
UID:3b35246601d2073b364c3002a2688c40ac88502f96c2a5727c5f3775
CATEGORIES:Conferences - Seminars
DESCRIPTION:Patrick Winkel\, Alice & Bob\nPlease join us for the QSE Cen
 ter Quantum Seminar with Patrick Winkel from Alice & Bob who will giv
 e the talk "Anomalous Frequency Shift in Low-Loss Superconducting Granula
 r Aluminum Resonators" on Thursday July 30th from 12:30 to 14:00.\nLocati
 on: CE 1 103\n\nPizzas will be available at 12:00. All are welcome to joi
 n.\n\nTITLE: "Anomalous Frequency Shift in Low-Loss Superconducting Granu
 lar Aluminum Resonators"\n\nSuperconducting high-kinetic inductance materi
 als like granular aluminum (grAl) are a versatile part of the circuit quan
 tum electrodynamics (cQED) toolbox. To further advance the use of grAl in 
 quantum devices\, it is indispensable to identify the dominant loss mechan
 isms. The standard approach pairs electromagnetic simulations of resonator
  geometry with measured temperature and power dependence of resonance freq
 uency and loss rate. Most materials follow the phenomenological theory of 
 two-level systems (TLSs) at low temperatures\, resulting in an initial dec
 rease of the resonance frequency with increasing temperature. In my presen
 tation\, I will report on the observation of an opposite behavior at the l
 owest temperatures in our devices: The resonance frequency initially incre
 ases with both temperature and readout power\, contradicting the standard 
 TLS model predictions. Part of the data can be explained by an alternative
  mechanism associated with the effect of superconducting quasiparticles in
  a granular system with a spatially-nonuniform gap. Yet\, the observed cha
 nge in the resonance frequency with temperature is not matched by a propor
 tional change in the loss rate. \n\nBIO: \nPatrick Winkel completed his 
 PhD in Physics at KIT under the supervision of Prof. Ioan Pop and Prof. Wo
 lfgang Wernsdorfer From 2016 to 2020. He then worked as a postdoctoral res
 earcher in Prof. Pop’s group at KIT from 2020 to 2021\, followed by a po
 stdoctoral position with Prof. Robert Schoelkopf at Yale University from 2
 022 to 2024. Since 2025\, he has been working as a Senior Team Lead at Ali
 ce & Bob.\n 
LOCATION:CE 1 103 https://plan.epfl.ch/?room==CE%201%20103
STATUS:CONFIRMED
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