TY - JOUR
T1 - How long does it take to implement a projective measurement?
AU - Strasberg, Philipp
AU - Modi, Kavan
AU - Skotiniotis, Michalis
N1 - Funding Information:
This research has received financial support from the DFG (project STR 1505/2-1), the Spanish MINECO FIS2016-80681-P (AEI-FEDER, UE), Spanish MICINN PCI2019-111869-2, the Spanish Agencia Estatal de Investigación, project PID2019-107609GB-I00, the Generalitat de Catalunya CIRIT 2017-SGR-1127, the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya, project ref. 001-P-001644(QuantumCat), the QuantERA Grant C’MON-QSENS!, and the Australian Research Council Future Fellowship FT160100073.
Publisher Copyright:
© 2022 European Physical Society.
PY - 2022/5
Y1 - 2022/5
N2 - According to the Schrödinger equation, a closed quantum system evolves continuously in time. If it is subject to a measurement however, its state changes randomly and discontinuously, which is mathematically described by the projection postulate. But how long does it take for this discontinuous change to occur? Based on simple estimates, whose validity rests solely on the fact that all fundamental forces in nature are finite-ranged, we show that the implementation of a quantum measurement requires a minimum time. This time scales proportionally with the diameter of the quantum mechanical object, on which the measured observable acts non-trivially, with the proportionality constant being around 10-5 s m-1. We confirm our bound by comparison with experimentally reported measurement times for different platforms. We give a pedagogical exposition of our argumentation introducing along the way modern concepts such as ancilla-based measurements, the quantum speed limit, and Lieb-Robinson velocity bounds.
AB - According to the Schrödinger equation, a closed quantum system evolves continuously in time. If it is subject to a measurement however, its state changes randomly and discontinuously, which is mathematically described by the projection postulate. But how long does it take for this discontinuous change to occur? Based on simple estimates, whose validity rests solely on the fact that all fundamental forces in nature are finite-ranged, we show that the implementation of a quantum measurement requires a minimum time. This time scales proportionally with the diameter of the quantum mechanical object, on which the measured observable acts non-trivially, with the proportionality constant being around 10-5 s m-1. We confirm our bound by comparison with experimentally reported measurement times for different platforms. We give a pedagogical exposition of our argumentation introducing along the way modern concepts such as ancilla-based measurements, the quantum speed limit, and Lieb-Robinson velocity bounds.
KW - Lieb-Robinson bounds
KW - macroscopicity
KW - quantum measurement
KW - quantum physics
KW - quantum speed limit
UR - http://www.scopus.com/inward/record.url?scp=85128126539&partnerID=8YFLogxK
U2 - 10.1088/1361-6404/ac5a7a
DO - 10.1088/1361-6404/ac5a7a
M3 - Article
AN - SCOPUS:85128126539
SN - 0143-0807
VL - 43
JO - European Journal of Physics
JF - European Journal of Physics
IS - 3
M1 - 035404
ER -