# Quantum coherence and neutrino detection

1. Aug 21, 2011

### exponent137

It is promised that the quantum coherence will help to improve various measurements.
Is it theoretically possible to improve detection of neutrinos with help of quantum coherence?

2. Aug 21, 2011

### BruceW

I'm not sure how quantum coherence can improve detection of neutrinos... Are you talking about a particular paper or article you've read, because I'm not familiar with the concept.

Often, neutrinos are detected by allowing them to collide with some kind of target, then detecting the electrons that they scatter. Measuring the properties of the electron can tell you if it was a neutrino that collided with it.

The thing about neutrinos is that they are very unlikely to interact with any given electron, so even a fairly large target won't stop all the neutrinos. You can say that the efficiency of detection is usually pretty low.

3. Aug 21, 2011

### exponent137

Are neutrinos interact with electron or with nuclei, where they produce electrons, or both?

Otherwise, I did not find any article, it only seems to me, that something theoretically should exist. I am very sure that practical possibilites are much lower than theoretical. So I ask for theoretical possibilities.

I admit, it is necessary to look how quantum coherence improve other measurements, for instance improved clock, or improved detection of gravitational waves.

Last edited: Aug 21, 2011
4. Aug 21, 2011

### xts

Most of neutrino detectors is based on elastic scattering of neutrinos on electrons. Such electron gets just kicked in direction close to the one of neutrino beam, and then may be detected. But some experiments utilise also other reactions, e.g. $\nu_e+n^0\rightarrow e^-+p^+$ on neutrons in nuclei.

See:
http://en.wikipedia.org/wiki/List_of_neutrino_experiments

5. Aug 21, 2011

### exponent137

More precise question. If we have a huge bose-einstein condensate, does it is more sensitive to neutrinos, than classical matter?

6. Aug 21, 2011

### yoda jedi

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7. Aug 21, 2011

### xts

Oh, yes, certainly!
Especially as both electrons and neutrinos (those interact in most of neutrino detectors) are eager to form such condenstate. Protons and neutrons, which are used in remaining 10% of detectors, are also perfect dough to bake BEC of them.

8. Aug 22, 2011

### exponent137

I think, if we built a huge bose-einstein condensate. Let us say, that number of electrons is such as it is in any now known detector. Does its detection possibility is significantly larger than in now common detectors. I hope for factor at least 100, not only 10%.

Because BEC behaves as one big electron.

I do not have theoretical background for such claim, but BEC can be used as measurement devices.

9. Aug 22, 2011

### xts

I must be disappointing. No BEC behaves like one big electron. Actually, electrons are fermions, so you can't make BEC of them...And even if you could, it woudn't affect their cross section on neutrinos scattering.

Better stay with Cherenkov's radiation in large tanks of water hidden in deep mines....

10. Aug 22, 2011

### exponent137

(Similarly as with Higgs boson in CERN).
Thank you.

But, BEC is built up also from electrons. Do they not share their energy with BEC?

(BEC=one big electron)=> one big atom or??

I need to re-read about use of BEC at precise measurements. Do anyone know something?

Last edited: Aug 22, 2011
11. Aug 22, 2011

### DrChinese

12. Aug 22, 2011

### yoda jedi

thanks DrChinese.

.

13. Aug 22, 2011

### ZapperZ

Staff Emeritus
This whole thread is puzzling because your starting premise here is very suspect.

How exactly is "quantum coherence" (assuming you know what it is) related to neutrino detection? Quantum coherence of WHAT property is involved here? So far, what you are lumping together appears to be word salad without a clear justification. BEC "built up" from electrons? What does that mean?

Zz.

14. Aug 22, 2011

### exponent137

It is only a speculation with not enough knowledge.
BEC is for bosons, not for fermions.
But a question remains:
How BEC help at improvement of some measurements? Ok, Google will also help.

15. Aug 22, 2011

### ZapperZ

Staff Emeritus
Then you have knowingly violated the PF Rules.

Don't look at me. YOU were the one who uttered these gems:

For whom?

This no longer concerns "coherence" and "neutrino detection". So now, back to the central question. What exactly is the connection between "BEC" and "measurement" that made you think they have anything to do with each other?

Zz.

16. Aug 23, 2011

### exponent137

It is necessary to read for me. I gave wrong sentences.

But, I gave questions and you question me.

I only gave questions, if it is possible to use coherent state for improved neutrino detection. It is not necessary that this is BEC, it can be any coherent state. It is not necessary that this can be built up in any future, I am interested only theoretically, because of physical principles.

Same links of BEC and measurements (I need to read them precisely):
http://first-quantum.net/symposium/2010/pdf/hirano_summerSchool2010.pdf
"precision measurements
gravity, angular velocity,
time, magnetic field, …
"
http://scienceblogs.com/principles/2009/01/ultra-cold_atoms_and_neutrino.php [Broken]

Last edited by a moderator: May 5, 2017
17. Aug 23, 2011

### ZapperZ

Staff Emeritus
This is because your question was vague and did not make any sense!

And I asked you why do you think that a coherent state of anything would improve neutrino detection. It appears as if you have no idea how neutrinos are detected currently. How would a coherent state of anything improve, say, the generation of cerenkov radiation that is produced that is the means of neutrino detection that we have currently? THAT is connection that is missing in your question.

If you are not able to supply that information, then the answer to your question is simple: NO.

Will that end this line of question?

Zz.

18. Aug 23, 2011

### edpell

What are the De Broglie wavelength of the neutrinos?

I do not see a point in have a detector particle that is larger than the particle you are trying to interact with.

19. Aug 23, 2011

### DrChinese

This being possibly a source for the original question: it is a very speculative idea, and really has nothing to do with coherence. It is so speculative - although grounded in "standard" science - that it is really not possible to answer a meaningful question about it.

My advice is to await further developments in this area, should there be any.

Last edited by a moderator: May 5, 2017
20. Aug 23, 2011

### xts

Depends on their energy. For those neutrinos we are able to measure (oreder of MeV) pretty small - order of femtometres.

What do you mean as 'detector particle' and its size? The particle interacting with the one you measure and its wavelength?
Oh yes, there is a point: if you want to measure multiple GeV particles, it could be difficult to use equally energetic particles as targets. And if you want to measure eny electro-weak particles (e.g. neutrinos) the easiest target are just slow electrons in matter.