Quantum Clocks and Stopwatches

2007 ◽  
pp. 235-278 ◽  
Author(s):  
Rafael Sala Mayato ◽  
Daniel Alonso ◽  
Iñigo L. Egusquiza
Keyword(s):  
Quantum Clocks

scholarly journals Quantum clocks and the temporal localisability of events in the presence of gravitating quantum systems

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Esteban Castro-Ruiz ◽  
Flaminia Giacomini ◽  
Alessio Belenchia ◽  
Časlav Brukner
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Quantum Systems ◽  
Indefinite Metric ◽  
Causal Order ◽  
Quantum Operations ◽  
Unitary Dilation ◽  
Local Quantum ◽  
Fixed Space ◽  
Quantum Clocks

AbstractThe standard formulation of quantum theory relies on a fixed space-time metric determining the localisation and causal order of events. In general relativity, the metric is influenced by matter, and is expected to become indefinite when matter behaves quantum mechanically. Here, we develop a framework to operationally define events and their localisation with respect to a quantum clock reference frame, also in the presence of gravitating quantum systems. We find that, when clocks interact gravitationally, the time localisability of events becomes relative, depending on the reference frame. This relativity is a signature of an indefinite metric, where events can occur in an indefinite causal order. Even if the metric is indefinite, for any event we can find a reference frame where local quantum operations take their standard unitary dilation form. This form is preserved when changing clock reference frames, yielding physics covariant with respect to quantum reference frame transformations.

Quantum Clocks and Stopwatches

2007 ◽  
pp. 217-255
Author(s):  
Rafael Sala Mayato ◽  
Daniel Alonso ◽  
Iñigo L. Egusquiza
Keyword(s):  
Quantum Clocks

scholarly journals Quantum clocks observe classical and quantum time dilation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander R. H. Smith ◽  
Mehdi Ahmadi
Keyword(s):  
Uncertainty Relation ◽  
Proper Time ◽  
Wave Packets ◽  
Center Of Mass ◽  
Time Dilation ◽  
Conditional Probability Distribution ◽  
Quantum Time ◽  
Mass Uncertainty ◽  
Quantum Clocks ◽  
Relativistic Particles

Abstract At the intersection of quantum theory and relativity lies the possibility of a clock experiencing a superposition of proper times. We consider quantum clocks constructed from the internal degrees of relativistic particles that move through curved spacetime. The probability that one clock reads a given proper time conditioned on another clock reading a different proper time is derived. From this conditional probability distribution, it is shown that when the center-of-mass of these clocks move in localized momentum wave packets they observe classical time dilation. We then illustrate a quantum correction to the time dilation observed by a clock moving in a superposition of localized momentum wave packets that has the potential to be observed in experiment. The Helstrom-Holevo lower bound is used to derive a proper time-energy/mass uncertainty relation.

scholarly journals Probabilistic Metrology Attains Macroscopic Cloning of Quantum Clocks

2014 ◽  
Vol 113 (26) ◽  
Author(s):  
B. Gendra ◽  
J. Calsamiglia ◽  
R. Muñoz-Tapia ◽  
E. Bagan ◽  
G. Chiribella
Keyword(s):  
Quantum Clocks

scholarly journals Motion and gravity effects in the precision of quantum clocks

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Joel Lindkvist ◽  
Carlos Sabín ◽  
Göran Johansson ◽  
Ivette Fuentes
Keyword(s):  
Gravity Effects ◽  
Quantum Clocks

Transportable quantum clocks based on a hydrogen generator with a small resonator

1989 ◽  
Vol 32 (4) ◽  
pp. 309-311 ◽  
Author(s):  
B. A. Gaigerov ◽  
F. S. Rusin ◽  
N. I. Pol'nikov ◽  
V. P. Sysoev ◽  
S. N. Ovchinnikov
Keyword(s):  
Hydrogen Generator ◽  
Quantum Clocks

scholarly journals Quantum Measurements, Energy Conservation and Quantum Clocks

2018 ◽  
Vol 530 (6) ◽  
pp. 1700388
Author(s):  
Nicolas Gisin ◽  
Emmanuel Zambrini Cruzeiro
Keyword(s):  
Energy Conservation ◽  
Quantum Measurements ◽  
Quantum Clocks

scholarly journals Coherence distillation machines are impossible in quantum thermodynamics

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Iman Marvian
Keyword(s):  
Coherent States ◽  
Full Rank ◽  
Fundamental Question ◽  
Quantum Thermodynamics ◽  
Mixed States ◽  
Zero Rate ◽  
Open Question ◽  
Quantum Clocks ◽  
Reference Clock

AbstractThe role of coherence in quantum thermodynamics has been extensively studied in the recent years and it is now well-understood that coherence between different energy eigenstates is a resource independent of other thermodynamics resources, such as work. A fundamental remaining open question is whether the laws of quantum mechanics and thermodynamics allow the existence of a coherence distillation machine, i.e., a machine that, by possibly consuming work, obtains pure coherent states from mixed states, at a nonzero rate. This is related to another fundamental question: Starting from many copies of noisy quantum clocks which are (approximately) synchronized with a reference clock, can one distill synchronized clocks in pure states, at a non-zero rate? Surprisingly, we find that the answer to both questions is negative for generic (full-rank) mixed states. However, at the same time, it is possible to distill a sub-linear number of pure coherent states with a vanishing error.

Experimental Measurement of Gravitational Time Dilation Using Transportable Quantum Clocks

2016 ◽  
Vol 59 (4) ◽  
pp. 402-404 ◽  
Author(s):  
V. F. Fateev ◽  
V. P. Sysoev ◽  
E. A. Rybakov
Keyword(s):  
Experimental Measurement ◽  
Time Dilation ◽  
Quantum Clocks
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