Questions tagged [atomic-clocks]

Use for atomic clocks - not any other type of clock.

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Is the accuracy of atomic clocks about engineering limits?

I read that a microwave with specific wavelength is shone on a bunch of atom to make them change energy state from ground to excited state, then they measure this difference in energy to determine its ...
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Why should a clock be "accurate"?

Having read that atomic clocks are more accurate than mechanical clocks as they lose a second only in millions of years, I wonder why it is necessary for a reference clock to worry about this, if the ...
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Do perfectly periodic motions (perfect clocks) exist in nature?

Periodic motions are used in clocks to measure time quantitatively. If we position a pendulum next to process, we can measure how long the process lasted. If the pendulum executed 3.78 periods it took ...
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Questions about setup and analysis of the gravitational time dilation experiment of Chou, Hume, Rosenband, Wineland (2010)

Notable experiments relating to (kinematic and gravitational) time dilation have been reported 2010 in article "Optical Clocks and Relativity", by C. W. Chou, D. B. Hume, T. Rosenband, D. J. ...
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Why do the cesium atoms in an atomic clock have to be tossed into the air like a fountain?

Even the NIST website for the standard F-1 clock and the new F-2 do not explain, exactly, why it helps (or is necessary) to make the cesium atoms appear, at least temporarily, weightless.... Wouldn't ...
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Could trapped ion quantum computers be used as (useful) atomic clocks?

Building a trapped ion quantum computer requires optimizing for different things than a cold atomic clock system. However, a lot of money is currently being dumped into rapidly developing this quantum ...
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Is a second now defined using 9,192,631,770 Hz or 9,192,631,770.2 Hz of a caesium atom?

This is obviously splitting hairs, to an extent, but I am genuinely curious... And it does make a difference... In several places, I have seen that .2 added on to the figure... Did the length of a ...
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Does special relativity's kinematic time dilation have a physical effect on matter, and how can you test this? [duplicate]

Kinematic time dilation or else named constant velocity time dilation is an apparent time dilation effect but with real consequences on how we measure time and our everyday life like the GPS ...
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Why the need for more sophisticated atomic clocks?

Why is there such a huge effort in building more sophisticated atomic clocks when the current ones achieve $1$ second of error every few hundred million years? Some achieve frequency stability close ...
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Least count of cesium clock and maximum possible significant figures for time

We know that a second is defined as being equal to the time duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the fundamental ...
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How robust is the international atomic time standard against malicious actors?

This answer explains the international atomic time standard (TAI). The fact that the Russian GLONASS and American GPS systems are referenced to their national clock systems, which are then ultimately ...
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What reference clock is an atomic clock measured against?

I looked at a few of the other posts regarding the accuracy of atomic clocks, but I was not able to derive the answer to my question myself. I've seen it stated that atomic clocks are accurate on the ...
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Can we provide a universal clock with atomic clock?

If we use normal clocks then due to the relativiy there will be misleading time, but what will happen with certain atomic clocks with less mistake and relative? If we can measure the time, what ...
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How does one get ticks of a clock from an atomic clock's microwave signal?

I understand that in an atomic clock there is a microwave signal that is locked to the frequency of the atomic rotation. However, if one wants to extract time ticks from the microwave signal: $v(t) =...
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What is the experimental evidence for gravitational time dilation?

There are many experiments done to prove time can be changed. I don't know lots of them, but I think the most popular (most cited) is to put a clock on a fast moving object (airplane), fly around and ...
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What is the advantage of a cesium atomic clock over a hydrogen maser as a frequency standard?

Even though both of them are frequency standard, and both are used simultaneously in almost every apex meteorology institute to keep the time, the cesium atomic clocks are more used in this field what ...
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Clocks only measure repetitions and not time [closed]

To measure time, we use clocks. From sophisticated atomic clocks to everyday wall clocks. When we measure the length of a time interval using a clock, we are really measuring the number of times the ...
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How atomic clock works?

I came across to atomic clocks when I was learning special theory of relativity in part Time dilation i simply want know how atomic clock defer from normal clocks.
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Atom in Radiation Reservoir (Cohen-Tannoudji formalism)

My task is to generalize the description in Cohen-Tannoudji's "Atom-Photon Interaction", p.284 from dipole only case onto forbidden transitions getting analogues of E.11 and E.13. Attempt: Took ...
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The term "Coherence" is overloaded!

I have troubles with modern terminology in the field of quantum information technologies. There are a lot of new terms that everyone is using and no-one takes time to explain, even though modern ...
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Atomic clock in expanding space

I have read these questions: Is there any paper analyzing the validity of Relativity in expanding space? The Great Atomic Clock of Kansas photons in expanding space: how is energy conserved? Is an ...
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Atomic spectroscopy with nuclear spin: hyperfine splitting

In $^{171} Yb$, nuclear spin $1/2$, there is a transition: $^{2}S_{1/2}(F=0) \rightarrow\; ^{2} F_{7/2} (F=3)$ In this paper on p.3 (top-left) they say that $m_F^{(f)} = 0$ at the final state $^2 F_{...
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Atomic clock in kitchen microwave or other random electronics?

Is it possible for atomic clocks to be put in anything, say a kitchen microwave? Or a regular wall clock? If so, why are they not in all clocks? Is it cost? How much does this tech cost to add to ...
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How to describe time dependence piece of a stationary state with average phase

I am reading this paper on the synchronization of atomic clocks via entanglement (https://arxiv.org/pdf/quant-ph/0004105.pdf) and can't figure out how they are using $\Omega = (E_{1} - E_{o})/\hbar$ ...
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Ramsey spectroscopy of atoms -- Heisenberg Picture

I was reading this thesis on the Ramsey spectroscopy, which deals with Ramsey spectroscopy of a two level system using the Heisenberg picture. This topic is dealt with in the Appendix A.1 of the given ...
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What do clocks measure?

I recently asked a question about the measurement of time, and it has become apparent that I'm really asking a set of related questions, the premises of which need to be shored up and articulated ...
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What makes the thorium-229 nuclear transition special?

Thorium-229 has a famous isomer with an excitation energy of only about 7.8 eV. As I gather from the wikipedia page, this transition was discovered essentially by accident from gamma ray spectroscopy....
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Are there transitions of mixed multipolarity in charged ions?

In nuclear physics transitions with mixed multipolarity, ex. (M1+E2), play an important role due to d-wave admixture. I was wondering if analogous situation has ever been considered in atomic ...
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How many caesium clocks are there on each GPS satellite ? Is there any other atomic clock on-board?

I am trying to find how many caesium atomic clocks are carried by each of the GPS satellites. And whether the satellites also carry other atomic clocks, such as rubidium or hydrogen clocks.
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Is an atomic clock itself affected by gravity?

Sometimes I read that only time flows at different rates in different conditions when atomic clocks shows a different time compared to atomic clocks at altitude. But sometimes I read that an atomic ...
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Are today's chip scale atomic clocks accurate enough to conduct my own test of time dilation?

Regarding the Symmetricom SA.45s Quantum™ Chip Scale Atomic Clock, is it accurate enough to test time dilation if I place one at sea level, and one on a mountain? It's accurate to 3.0⋅10−10 per month....
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What is exactly the difference between an active and passive frequency standard?

In the case of passive atomic frequency standard, we take an atomic reference which has a resonant frequency response centered at certain particular frequency. Then we take a local oscillator and tune ...
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2 answers
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Where is the periodic nature in the Cs atomic clock? [closed]

In case of pendulum clock,lets say one swing ticks one second..but what is the analogy in case of CAESIUM atomic clock? Is 9,192,631,770 ticks is equivalent to one tick in pendulum clock? And how we ...
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Timekeeping , optical clocks, and precision

I am having trouble understanding something: The concept of time measurement. So I want to simply this as much as possible to get an intuitive understanding: We define the second by the time it ...
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What ticks in an optical clock?

After reading several articles about current state of the art clocks, I'm still wondering one thing: What ticks? As I understand it, in cesium clocks time is measured in cycles of a microwave ...
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Time Synchronization Between 2 GPS Controlled Rubidium Clocks [closed]

I have 2 GPS Controlled Rubidium Clocks I need it to be synchronized to one another to the level of a microsecond. My question is what is the max phase (ns) allowed from the clock's input 1pps, for ...
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6 votes
3 answers
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Cooling of atomic clocks

I have read of cooling atoms to one-quarter of one-thousandth of a degree above absolutely zero. According to Physicist William Phillips, this improves the measurement of the ticking frequency. I have ...
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Working out atomic clock accuracy using measured frequency Hz, error and beat Hz

I've got a question where $200,000\,{\rm Hz}$ applied to the Cesium atoms and from the mismatch with the atom's natural frequency, we get a "beat" of $2\,{\rm Hz}$. The error is $1\%$. The accuracy ...
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5 answers
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Why do atomic clocks only use caesium?

Modern atomic clocks only use caesium atoms as oscillators. Why don't we use other atoms for this role?
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How do we know that the cesium-beam frequency used in atomic clocks is always the same?

Atomic clocks use cesium-beam frequency to determine the length of a second. This has shown that the period of orbit of the earth is decreasing. But what experiment showed that cesium-beam's period ...
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9 votes
1 answer
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What's the smallest height difference over which gravitational time dilation has been experimentally observed?

In a famous experiment, reported in Optical Clocks and Relativity. CW Chou, DB Hume, T Rosenband and DJ Wineland. Science 329 no. 5999 pp. 1630-1633 (2010); NIST eprint. and nicely described in ...
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