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SUMMARY:Quantum metrology with interacting many-body systems: Fundamental 
 bounds and attainability
DTSTART:20231130T120000
DTEND:20231130T133000
DTSTAMP:20260603T080033Z
UID:80c6871f3a97b35ed8fc7ec3b6b803a1db8374e93bba132cbeae85a6
CATEGORIES:Conferences - Seminars
DESCRIPTION:Martí Perarnau-Llobet\nPlease join us for the QSE Center Q
 uantum Seminar with Prof. Martí Perarnau-Llobet from University of Gen
 eva who will speak on Thurdsay\, November 30\, about  "Quantum metrolog
 y with interacting many-body systems". \n\nLocation: BS 270\n\nPizzas wi
 ll be available before the seminar at 12:00. All PhDs\, postdocs\, studen
 ts\, and PIs are welcome to join us.\n \nTITLE: Quantum metrology with i
 nteracting many-body systems: Fundamental bounds and attainability \n\n 
 \n\nABSTRACT:\n\nStandard quantum metrology protocols exploit delicate qua
 ntum states\, like entangled or squeezed states\, to enhance the precision
  of measurements beyond the standard shot-noise limit. Usually\, this adva
 ntage is lost in the presence of dissipation or noise. A potential avenue 
 to overcome this limitation is to consider many-body interacting systems\,
  where the presence of interactions can lead to non-trivial open dynamics 
 and steady states that can be useful for metrology.  A prominent example 
 is critical quantum metrology\, which uses a probe close to a (quantum) ph
 ase transition for very precise measurements.  \n\n \n\nIn this talk\, 
 I will present progress in this direction by considering the estimation of
  parameters\, e.g. temperature or magnetic fields\, from measurements of a
  quantum probe in thermal equilibrium. For the probe\, we will consider an
  interacting few or many-body quantum system. I will show a general bound 
 on the measurement precision (the Quantum Fisher Information) valid for ar
 bitrary Hamiltonians of the probe\, which shows a quadratic scaling with t
 he number of bodies. Despite a formal resemblance with the Heisenberg limi
 t\, we will see that this bound can be saturated by purely classical (i.e.
  commuting) interacting Hamiltonians. A quantum advantage becomes possible
  for gapped Hamiltonians in the low temperature regime. I will then discus
 s how to engineer optimal probes\, featuring locally interacting two-body 
 Hamiltonians\, that can approach such limits for the estimation of relevan
 t magnitudes (e.g. magnetic fields and temperature).  Finally\, I will di
 scuss the crucial role of feedback and measurement adaptativity to saturat
 e these bounds in the presence of prior uncertainty. \n\n \n\nThis talk 
 is based on joint work with Paolo Abiuso (soon to appear in arxiv)\, and a
 lso on arXiv:2211.01934 and arXiv:2211.07688.\n\n\nBIO:\nMartí Perarn
 au-Llobet is an Assistant Professor at the University of Geneva\, since M
 ay 2020. Previously\, he was postdoc at the Max Planck Institute for Quant
 um Optics in Garching (2016-2020) in the Theory group of Ignacio Cirac\, a
 nd did the Phd in ICFO (2012-2016) in Acín's group.\n\n 
LOCATION:BS 270 https://plan.epfl.ch/?room==BS%20270
STATUS:CONFIRMED
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