Questions tagged [atomic-clocks]

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

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Why the Chipping Rate of 1.023 MHz for the GPS L1 C/A Signal?

Why was the chipping rate for the GPS L1 C/A signal chosen to be 1.023 MHz (1023 chips per symbol, one symbol per ms)? It seems to me like you'd want to get one chip as close as possible to an ...
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0answers
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Effect of variation in day length on timekeeping

I was reading about atomic clocks when I came to know that precise measurements of time have shown that the time for earth's rotation is slightly more that 24 hrs (on the order of 10^-3). I was ...
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2answers
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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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1answer
75 views

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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1answer
301 views

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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1answer
62 views

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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1answer
39 views

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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2answers
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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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1answer
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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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1answer
157 views

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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5answers
887 views

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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1answer
569 views

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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4answers
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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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4answers
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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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1answer
93 views

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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2answers
69 views

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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1answer
72 views

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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1answer
97 views

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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0answers
54 views

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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3answers
2k views

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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1answer
123 views

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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5answers
17k views

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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3answers
1k views

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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1answer
113 views

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 ...