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UID:6a1bd9978f549
DTSTART:20250626T100000Z
SEQUENCE:0
TRANSP:OPAQUE
DTEND:20250626T110000Z
LOCATION:Seminar Room
SUMMARY:ICFO | MATTHEW DUSCHENES
CLASS:PUBLIC
DESCRIPTION:Moments of ensembles of unitary evolutions play a central role 
 in quantum information theory as they capture the statistical properties o
 f dynamics with some form of randomness. Indeed\, concepts such as approxi
 mate t-designs arise when comparing how close an associated moment operato
 r of a given ensemble is to that of another\, reference\, ensemble. Despit
 e their tremendous importance\, the analysis of moment operators for quant
 um channels\, which describe noisy quantum circuits\, has not been explore
 d. In this work we develop a general theoretical framework to study moment
  operators for channels\, with a special focus on determining ensembles th
 at can be used as points of reference. By studying exactly concatenated mo
 ment operators within general Hilbert spaces\, for all moment orders t\, w
 e give operational meaning to their spectra and norms. We show that such q
 uantities can be used to analyze many ensemble properties\, in particular 
 concentration phenomena in noisy quantum circuits. We proceed to perform t
 heoretical and numerical studies which show that different types of noise 
 can decrease the norm of the moment operators (e.g. depolarization)\, as w
 ell as increase it (e.g. amplitude damping). We finish our work with a des
 cription of several future research directions based on the developed form
 alisms that are relevant to error mitigation. This work is done in collabo
 ration with Diego Gar&ccedil\;ia-Martin and Marco Cerezo at Los Alamos Nat
 ional Laboratory and Zoe Holmes at EPFL.\n&nbsp\;
DTSTAMP:20260531T064751Z
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