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

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 Classical and Nonclassical Time Dilation for Quantum Clocks

2020 ◽  
Vol 124 (16) ◽  
Author(s):  
A. J. Paige ◽  
A. D. K. Plato ◽  
M. S. Kim
Keyword(s):  
Time Dilation ◽  
Quantum Clocks

scholarly journals Universal quantum modifications to general relativistic time dilation in delocalised clocks

Quantum ◽  
2020 ◽  
Vol 4 ◽  
pp. 309 ◽  
Author(s):  
Shishir Khandelwal ◽  
Maximilian P.E. Lock ◽  
Mischa P. Woods
Keyword(s):  
Quantum Interference ◽  
Degrees Of Freedom ◽  
Proper Time ◽  
World Line ◽  
Weak Field ◽  
Time Dilation ◽  
Theory Of Relativity ◽  
Low Velocity ◽  
Significant Discrepancy ◽  
Quantum Clocks

The theory of relativity associates a proper time with each moving object via its world line. In quantum theory however, such well-defined trajectories are forbidden. After introducing a general characterisation of quantum clocks, we demonstrate that, in the weak-field, low-velocity limit, all ``good'' quantum clocks experience time dilation as dictated by general relativity when their state of motion is classical (i.e. Gaussian). For nonclassical states of motion, on the other hand, we find that quantum interference effects may give rise to a significant discrepancy between the proper time and the time measured by the clock. The universality of this discrepancy implies that it is not simply a systematic error, but rather a quantum modification to the proper time itself. We also show how the clock's delocalisation leads to a larger uncertainty in the time it measures – a consequence of the unavoidable entanglement between the clock time and its center-of-mass degrees of freedom. We demonstrate how this lost precision can be recovered by performing a measurement of the clock's state of motion alongside its time reading.

Experimental Measurement of Turbulent Diffusion, Initial Dilution and T90

1986 ◽  
Vol 18 (11) ◽  
pp. 131-140
Author(s):  
Edmundo Garcia Agudo ◽  
Jose Leomax dos Santos
Keyword(s):  
Experimental Measurement ◽  
Tracer Technique ◽  
Initial Dilution ◽  
Coastal Cities ◽  
Actual Solution ◽  
The World ◽  
Visual Aid ◽  
Proper Design ◽  
Key Aspects ◽  
Bacterial Concentrations

The final disposal of sewage using submarine outfalls has become an actual solution for coastal cities all over the world. In order to get the best results it is necessary to carry out specific studies for the proper design of the outfall. Dilution and decrease in bacterial concentrations are two key aspects for the design. Radioisotope tracers have been used extensively in studies performed in some Brazilian waterbodies where outfall systems exist or are to be installed. As far as dilution measurement is concerned, both point and continuous radiotracer injections can provide useful results. The T90 measurements can be better accomplished using a combined tracer technique for sampling the sewage field, using the radiotracer for dilution measurement and rhodamine B as a visual aid. Typical results of dilution measurement using both techniques mentioned, as well as a summary of T 90 results obtained for the Santos, Fortaleza and Maceió outfalls are presented.

The Equivalence Principle

2018 ◽  
Author(s):  
David M. Wittman
Keyword(s):  
General Relativity ◽  
Special Relativity ◽  
Equivalence Principle ◽  
Time Dilation ◽  
Gravitational Redshift ◽  
Coordinate Systems ◽  
Spacetime Metric

The equivalence principle is an important thinking tool to bootstrap our thinking from the inertial coordinate systems of special relativity to the more complex coordinate systems that must be used in the presence of gravity (general relativity). The equivalence principle posits that at a given event gravity accelerates everything equally, so gravity is equivalent to an accelerating coordinate system.This conjecture is well supported by precise experiments, so we explore the consequences in depth: gravity curves the trajectory of light as it does other projectiles; the effects of gravity disappear in a freely falling laboratory; and gravitymakes time runmore slowly in the basement than in the attic—a gravitational form of time dilation. We show how this is observable via gravitational redshift. Subsequent chapters will build on this to show how the spacetime metric varies with location.

Energy and Momentum

2018 ◽  
Author(s):  
David M. Wittman
Keyword(s):  
Time Dilation ◽  
Speed Of Light ◽  
Massless Particles ◽  
The Everyday ◽  
Low Speeds ◽  
Energy And Momentum ◽  
Deep Relationship ◽  
Insight Into ◽  
Momentum Relation

Tis chapter explains the famous equation E = mc2 as part of a wider relationship between energy, mass, and momentum. We start by defning energy and momentum in the everyday sense. We then build on the stretching‐triangle picture of spacetime vectors developed in Chapter 11 to see how energy, mass, and momentum have a deep relationship that is not obvious at everyday low speeds. When momentum is zero (a mass is at rest) this energy‐momentum relation simplifes to E = mc2, which implies that mass at rest quietly stores tremendous amounts of energy. Te energymomentum relation also implies that traveling near the speed of light (e.g., to take advantage of time dilation for interstellar journeys) will require tremendous amounts of energy. Finally, we look at the simplifed form of the energy‐momentum relation when the mass is zero. Tis gives us insight into the behavior of massless particles such as the photon.

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