title: Feedback cooling of the normal modes of a massive electromechanical system to submillikelvin temperature.
abstract: We apply a feedback cooling technique to simultaneously cool the three electromechanical normal modes of the ton-scale resonant-bar gravitational wave detector AURIGA. The measuring system is based on a dc superconducting quantum interference device (SQUID) amplifier, and the feedback cooling is applied electronically to the input circuit of the SQUID. Starting from a bath temperature of 4.2 K, we achieve a minimum temperature of 0.17 mK for the coolest normal mode. The same technique, implemented in a dedicated experiment at subkelvin bath temperature and with a quantum limited SQUID, could allow to approach the quantum ground state of a kilogram-scale mechanical resonator.
authors.affiliation: Istituto di Fotonica e Nanotecnologie, CNR-Fondazione Bruno Kessler, 38100 Povo, Trento, Italy. vinante@science.unitn.it
authors.forename: A
authors.initials: A
authors.lastname: Vinante
authors.forename: M
authors.initials: M
authors.lastname: Bignotto
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authors.initials: M
authors.lastname: Bonaldi
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authors.initials: M
authors.lastname: Cerdonio
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authors.lastname: Conti
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authors.lastname: Falferi
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authors.lastname: Liguori
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authors.initials: S
authors.lastname: Longo
authors.forename: R
authors.initials: R
authors.lastname: Mezzena
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authors.lastname: Ortolan
authors.forename: G A
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authors.lastname: Prodi
authors.forename: F
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authors.lastname: Salemi
authors.forename: L
authors.initials: L
authors.lastname: Taffarello
authors.forename: G
authors.initials: G
authors.lastname: Vedovato
authors.forename: S
authors.initials: S
authors.lastname: Vitale
authors.forename: J-P
authors.initials: JP
authors.lastname: Zendri