- #36
heldervelez
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How to derive the value of Mass property of particles?
What is the hardest question to ask a quantum physicist?
In summary, my friend thinks he can answer any question related to Quantum physics (although he claims he won't be able to answer known unknowns i.e 'the mass of the Higgs-Boson particle'). However, I would like to challenge him with a series of the hardest questions anyone on this forum can put to him.
- #37
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But it is made of quantum particles, isn't it?Phyisab**** said:
- #38
amir11
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a bit late but I think very simply ask him what the photon is.
probably every one knows the famous answer by einstien!
probably every one knows the famous answer by einstien!
- #39
humanino
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It's a quantum of the photon field. You may as well say "but what is the photon field ?", however one can play this game with any question. Same game could be played with "but what is a quantum, really ?". My point is : within QED, a photon is a well-defined mathematical concept, and if you want to go into "but what is it really ?" the only answer you will get is that QED works fine as far as experiment is concerned.amir11 said:
- #40
Count Iblis
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humanino said:
That's why all physicists should believe in Tegmark's ideas about reality being purely mathematical in nature: All that exists is only abstract math, and thus our universe is the mathematical model that describes it and nothing more.
- #41
Frame Dragger
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The same question parents and teachers have struggled with forever! "Where do baby Quantum Physicists come from?" 
- #42
torquil
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Count Iblis said:
Since I'm reading Penrose's "Road to Reality" at the moment, I've been exposed to a lot of discussion about the "nature of reality". However, I find the concept of "reality" to be much less well-defined than the physical theories that are used in practice.
For me it is not sufficiently well-defined to talk about the nature of reality.
What is great however, is that the ability of physics to describe/predict our observations of all kinds of phenomena is improving with time, independently of how one wishes to define "reality".
Torquil
- #43
yoda jedi
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not only quantum physicists
i like it !
easy one !
i like it !
well said !
Demystifier said:
i like it !
easy one !
jtbell said:
i like it !
peteratcam said:
well said !
- #44
amir11
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humanino said:
As far as I know a photon has not got any clear description even in terms of QED. I ment the quot by einstien
: "All the fifty years of conscious brooding have brought me no closer to the answer to the
question: what are light quanta? …..…… Of course, today every rascal thinks he knows the
answer, but he is deluding himself.”
- #45
Living_Dog
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realblonde said:
Is the cat alive?
- #46
Frame Dragger
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Living_Dog said:
Do that one better and ask him about 'Wigner's Friend'.
EDIT: If you want to trip him up with something obvious, ask him what the difference is between the 'Sum Over Histories' for a particle, and the "Path Integral" for a particle. If he says anything other than, "same thing", shoot him, he's an alien.
- #47
torquil
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amir11 said:
What was Einsteins objection to the description of the photon in QED? Is it simply related to his general objection to quantum physics and its non-local measurement aspects?
Or is it related to technical aspects of QED, e.g. regarding the definition of an asymptotically free single photon in/out state, in the presence of vacuum fluctuations? Or maybe problems with convergence of perturbation theory?
Btw, do these technical aspects pose any problem in pure QED?
Torquil
- #48
humanino
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Again, the photon is well defined mathematical concept in QED. It's actually quite funny that you decided to use a quote from Einstein to justify your attitude, because Einstein himself came up with the idea of a photon. So you might as well have used a quote from Planck rejecting Einstein's idea of the photon.amir11 said:
- #49
jtbell
Staff Emeritus
Science Advisor
Homework Helper
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amir11 said:
It's been more than fifty years since Einstein died! Don't you think there might be a possibility that we might have learned a few things about photons since then?
- #50
DrChinese
Science Advisor
Gold Member
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Frame Dragger said:The same question parents and teachers have struggled with forever! "Where do baby Quantum Physicists come from?"
LOL
- #51
conway
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How about this one: How would the universe be different if there were no such thing as photons?
- #52
tiny-tim
Science Advisor
Homework Helper
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conway said:
"without form, and void"?
- #53
Frame Dragger
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tiny-tim said:"without form, and void"?
A Biblical reference... wow. This is a gooooood thread.
I submit also that this could be taken as, "What is the hardest question [for YOU] to ask a quantum physicist?" in which case... we have a whole new challenge. Then perhaps the hardest question would be, "Why do you love that stupid Boson and not the children?!"
@DrChinese:
What can I say, sometimes you must turn to the classics in all things. - #54
Tao-Fu
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Count Iblis said:
Hmm, I would stray more toward our models being purely mathematical. Science consists of models or descriptions. We can only ever make definitions and tabulate our observations. We can not ever address the question of what anything actually "is". For example, I can tabulate a set of observed properties for an electron but I can't really say what an electron IS.
Our descriptions correspond to mathematical models but I think it unfounded to claim that reality/the universe _is_ a mathematical model. The universe is not equivalent to our descriptions of it.
- #55
ytuab
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If we can't say what "spin" actually is (not only as the "mathematical" models), we can't say what the electorns and the quantum phenomena actually are. (See this thread).
Because all the electrons always have "spin" in QM
If all phenomena in this world are caused by the quantum mechanics, mustn't we say what any phenomena around us actually are forever?
Because all the electrons always have "spin" in QM
If all phenomena in this world are caused by the quantum mechanics, mustn't we say what any phenomena around us actually are forever?
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- #56
yoda jedi
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Tao-Fu said:
i agree.
they just, mislead one for other.
(description for reality or reality by description)
REALITY is independent of explanations.
ytuab said:
i agree, and at the end in any case, spin are relative (i say, the orientation).
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- #57
kikushiyo
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Another question (for Unification people) : why perturbative gaussian fixed points are expected to drive the flow of from one theory to another ?
- #58
torquil
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Regarding this debate about what "reality" really is, I will hereby proclaim in the spirit of Nietzsche:
Reality is dead!
According to Wikipedia, the historic Nietzsche quote about god is "Nietzsche's way of saying that the "God" of the times (religion and other such spirituality) is no longer a viable source of any received wisdom".
In the same manner, I believe that it does not give us any valuable wisdom by debating what is real and what is not.
Science however, is fortunately alive.
Torquil
Reality is dead!
According to Wikipedia, the historic Nietzsche quote about god is "Nietzsche's way of saying that the "God" of the times (religion and other such spirituality) is no longer a viable source of any received wisdom".
In the same manner, I believe that it does not give us any valuable wisdom by debating what is real and what is not.
Science however, is fortunately alive.
Torquil
- #59
yoda jedi
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amir11 said:
well...
maybe:
The photon is no strict particle and nonlocality is far from
being proven Fachverband Theoretische und Mathematische Grundlagen der Physik
2010.
Karl Otto Greulich.
Two aspects of philosophical discussions on physics are the wave particle
dualism and non locality including entanglement. However the
strict particle aspect of the photon, in the common sense view, has
never been proven. The accumulation time argument, the only experimental
verification of a strictly particle like photon, has so far not
yet been satisfied. Also, experiments thought to prove nonlocality
have loophole which have so far not yet been safely closed, and now
an even more serious loophole emerges. Thus, also nonlocality cannot
be seen as proven. This demands some fine tuning of philosophical
discussions on critical experiments in physics.
--------------
and apart
Single Molecule Experiments Challenge the Strict Wave-Particle Dualism of Light
http://www.mdpi.com/1422-0067/11/1/304/pdf
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- #60
Troponin
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Too easy...
A much more difficult problem would be finding a question on Quantum Physics that I can answer.
A much more difficult problem would be finding a question on Quantum Physics that I can answer.
- #61
pst007x
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This may be just my mis-understanding, but... If at one time all particles were entangled, at the point of origin, why not now?
- #62
Derrezed
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jtbell said:
All of them, and none of them.
- #63
Derrezed
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pst007x said:
I am curious about this one as well!
- #64
PatrickPowers
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pst007x said:
I once posted this question to a physics group and the unanimous reply was that everything IS entangled. This entangling is so complicated that it is unpredictable, random, of no use, so it is of no practical importance.
- #65
thedeester1
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You could ask him how he's doing. Does he want a drink...and hows the Kids...You did say he was a Freind!
- #66
PatrickPowers
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"What's the hardest question I could ask you about quantum physics?"
Nyuck nyuck nyuck.
Nyuck nyuck nyuck.
- #67
PoacherKid
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I was just browsing the internet trying to learn new things like most not normal teenage kids that happen to be nerds. When I came upon this question.
"If no one looks is the moon really there"
I kinda laughed because this is one of those deep physiological questions that only dumbos ask.
Other questions that idiots ask are "If a tree falls and know one is there to hear it, does it make a sound" and "What came first? The chicken or the egg?" It is the egg obviously. This moon question struck me as even dumber than the chicken one though, so I felt compelled to make an account to rant and rage at the guy asking this question. First of all it is very unlikely that everyone in the world will just one day happen to not look at the moon at the same time. That is beside the point but still... If everyone was to not look at the moon at the same time it would still exist. If the moon does not exist and or never did exist we would not exist either, because the moon makes these things called tides and these things called tides control the currents in the ocean which in turn control the movement of hot and cold water. This hot and cold water controls the temperature of the air above it which creates air currents in the sky known as "Wind". This can create big storms which control what goes on in our lives. You may think that the weather is not very important but in all honesty we would not be alive without these tides because tides have existed since the first oceans began to form. Even if these oceanic tides did not affect our weather we still need to keep in mind that the moon also creates a tide in our Earth's crust. Each night the crust of the Earth actually bulges out about 12 to 18 inches creating mass amounts of friction that help to heat the mantle below us. Without these crust tides Earth may have frozen solid millions of years ago just like mars. So in much simpler words we all know that the moon exists even when we are not looking at it because we are here and breathing.
"If no one looks is the moon really there"
I kinda laughed because this is one of those deep physiological questions that only dumbos ask.
Other questions that idiots ask are "If a tree falls and know one is there to hear it, does it make a sound" and "What came first? The chicken or the egg?" It is the egg obviously. This moon question struck me as even dumber than the chicken one though, so I felt compelled to make an account to rant and rage at the guy asking this question. First of all it is very unlikely that everyone in the world will just one day happen to not look at the moon at the same time. That is beside the point but still... If everyone was to not look at the moon at the same time it would still exist. If the moon does not exist and or never did exist we would not exist either, because the moon makes these things called tides and these things called tides control the currents in the ocean which in turn control the movement of hot and cold water. This hot and cold water controls the temperature of the air above it which creates air currents in the sky known as "Wind". This can create big storms which control what goes on in our lives. You may think that the weather is not very important but in all honesty we would not be alive without these tides because tides have existed since the first oceans began to form. Even if these oceanic tides did not affect our weather we still need to keep in mind that the moon also creates a tide in our Earth's crust. Each night the crust of the Earth actually bulges out about 12 to 18 inches creating mass amounts of friction that help to heat the mantle below us. Without these crust tides Earth may have frozen solid millions of years ago just like mars. So in much simpler words we all know that the moon exists even when we are not looking at it because we are here and breathing.
- #68
bahamagreen
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I'm going to have to agree with some above that the premise of "being able to answer any question" about QM is not totally far fetched... in the sense that it does present a self defined internally complete and consistent system... kind of in the way that a swimmer can cross a river without having to touch bottom (because he knows how to swim).
Maybe try a more direct challenge at a more fundamental level:
Ask him to write down a random number, then demonstrate that the number is random.
Follow-up question: If picking a random natural number, mustn't that number be infinite?
Maybe try a more direct challenge at a more fundamental level:
Ask him to write down a random number, then demonstrate that the number is random.
Follow-up question: If picking a random natural number, mustn't that number be infinite?
- #69
mpv_plate
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realblonde said:
We never heard back from realblonde... And I would like to know so many things!