Throwing a tennis ball through a wall

[Crosstalk]

I was thinking that because the tennis ball is made of protrons, electrons, neutrons, and other things that can quantum tunnel by theirselves, there would be a chance (Amasingly small, though, although I can't give an estimate I would say on the order of 10^-100000000000000000) that all the particles in the ball would tunnel at once, and go right through the wall. There might also be an even smaller chance that that would happen and the particles would all rearrange themselves back into the ball, but my way off estimate for the probability of that would be about 10^-10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000, but this estimate is probably higher than the actual chances.

 

[jackle]

Asking questions (even meaningless ones) is how we learn. I don't see a problem with it.

It has occurred to me that having said this, I might be opening the flood gates for people to assert all kinds of silly theories. I do approve of monitoring and checking threads in the interest of quality, but I can't seem to find the rules for this forum.

That aside, I'd like to think that nobody should be afraid to ask a 'silly' question.

In general I would appreciate an estimate more than the last post, when it is presented with the correct rigour. eg. What assumptions have we made? Where did the number 10^-(10^300 and something)? come from? Why do you think this? I think this thread is being ignored because it is too silly at the moment.

My guess is that there is always a chance for our tennis ball but that any estimate will be hopelessly wrong, even when attempting it seriously. There are probably many ways the tunnelling 'could' happen and the trick would be to estimate the most likely way as an approximation to the real thing.

 

[jackle]

the most 'likely' way

 

[jackle]

the 'real' thing

 

[SizarieldoR]

Sure. In theory it is possible.

 

[jackle]

...a 'chance'...

 

[Chaos' lil bro Order]

Sometimes I wonder if people take the ideas coming out of QM and incorrectly apply them to macroscopic objects for the sake of their own philosophical confirmation. Then I remember that I did exactly this earlier in this thread and ZapperZ showed my that I was wrong to do so. Then I see later in this thread people making the exact same mistake. I would point those people to Zapper's earlier comments to clear up any confusion they may be having.

 

[Chaos' lil bro Order]

Farsight

How could a tennis ball actually be a Bose-Einstein condensate? Isn't that too large of a hypothetical to hold any illustrative meaning? I'm very ignorant in this area, but is there any way, even theoretically that a macroscopic tennis ball could be treated as a Bose-Einstein condensate?

 

[Greenman]

I do think we must take QM seriously and classical mechanics as a prejiduce. The wavefunction does describe reality. However it is entirely logical that the 'predictions' of QM are 100% true yet not completely describe the entire system even in it's domain.

Could you elaborate on this please?

or could someone else explain what he means by that.

thanks :D

 

[vanesch]

Could you elaborate on this please?

or could someone else explain what he means by that.

thanks :D

Note that this thread was 3 years old...

 

[Haelfix]

As I understand quantum mechanics, my answer would be that indeed it is possible for a book to tunnel through a table. Just that the odds of this happening are like 10^10^10^10^10^10^...^10^-(some large number). So astronomically small relative to the timescales of both the universe and myriad other events from occurring, that its essentially for all physical purposes zero.

When I was taking my competency exam in grad school, one of the past questions was to derive an order of magnitude estimate for a molecule of hydrogen sitting on a table to tunnel through a 1 fm graphene wall with some given density. The accepted answer was ridiculously tiny, but also a notoriously controversial question b/c depending on what effects you take into account (eg what potential wall do you want to ansatz), the answer changes by hundreds of orders of magnitude!

 

[bjacoby]

As I understand quantum mechanics, my answer would be that indeed it is possible for a book to tunnel through a table. Just that the odds of this happening are like 10^10^10^10^10^10^...^10^-(some large number). So astronomically small relative to the timescales of both the universe and myriad other events from occurring, that its essentially for all physical purposes zero.

When I was taking my competency exam in grad school, one of the past questions was to derive an order of magnitude estimate for a molecule of hydrogen sitting on a table to tunnel through a 1 fm graphene wall with some given density. The accepted answer was ridiculously tiny, but also a notoriously controversial question b/c depending on what effects you take into account (eg what potential wall do you want to ansatz), the answer changes by hundreds of orders of magnitude!

Your answer, though reflective of common physics assertions, simply shows how far physics has moved away from science and toward magic and mysticism. Part of the problem is that mathematics has become worshiped as a substitute for science. Mathematics is regarded as more real than reality. Physicists commonly talk about fields and point charges and imaginary numbers as if these things actually has some real meaning in a physical world. Sorry mathematics is abstract. It does not need to agree with experiment. It only needs to be some self-consistent mental concoction.

So given such a mindset, we find hideous statements being passed off as physics. These include the mathematical extensions of QM such as tennis balls tunneling through walls and bowling balls being reflected from a table edge. I happen to know a physicist who actually calculated the bowling ball reflection. Sorry. You can roll them at a table edge FOREVER and they'll never ever come back. Why? Because the REAL ACTUAL energy functions at the edge of the table are not the ideal mathematical "wells" and "steps" that are so mathematically convenient. They turn out to be nice smooth falling off curves that could never produce a minor reflection let alone one on a bowling ball. Doubtless the same is equally true for real tennis balls.

So the bottom line is that all these stories of the "weirdness" of QM when transferred to daily life make great fodder to impress a class full of freshmen, but the truth is that it's nothing but Hollywood and just as much fiction as their latest movies. So the tunneling of a tennis ball may be "impossible" according to QM mathematical models, but a real tennis ball is different.

Now the question as to whether or not a tennis ball actually CAN pass through a wall under the right conditions (not simple QM statistical ones) is anther question all together. We do know that a wall is mostly empty space. There are hints (but nothing more) in stories and myths that saints and others can develop such an ability. Is it true or Memorex? Well who knows? Fact is one has to suggest that in some manner (but not a straight quantum mechanical one) it actually MAY be possible for a tennis ball to go through a wall, or the temperature in a room to be lowered, or a bowling ball to be reflected from a table edge. And the reason we must allow this possibility is the rule that says saying some physical phenomenon is "impossible" is the mathematical equivalent of saying "I'm a moron". Mathematics can express impossibility by definition. Physics has no such luxury.

I will leave the proof of this last theorem as an exercise for the interested student.

 

[DrChinese]

As I understand quantum mechanics, my answer would be that indeed it is possible for a book to tunnel through a table. Just that the odds of this happening are like 10^10^10^10^10^10^...^10^-(some large number).

Paraphrasing from the movie Dumb and Dumber:

So there IS a chance that I will end up married to Angelina Jolie...

 

[Greenman]

Note that this thread was 3 years old...

So does everything ZapperZ said 3 years ago still stand today?

 

[Greenman]

Does this mean that a tennis ball COULD INDEED go through a wall:

http://www.sciencedaily.com/releases/2009/09/090923151730.htm

 

[ZapperZ]

Does this mean that a tennis ball COULD INDEED go through a wall:

http://www.sciencedaily.com/releases/2009/09/090923151730.htm

The fact that these are josephson junctions under superconducting conditions means nothing to you? Notice my earlier argument that a tennis ball must have ALL parts of it in coherence with each other for the WHOLE tennis ball to tunnel through. So why do you think people go through all that trouble to do most of these experiments in the superconducting state?! I mean, look at the Delft/Stony Brook's Schrodinger Cat-state experiments. Why did they go through all that trouble to do their experiments in the superconducting state? Do you think they could maintain 10^11 particles in a coherent state if they don't go through such lengths?

Moral of the story: preservation of coherence is NOT EASY! Even after just ONE single interaction, that has been shown to be https://www.physicsforums.com/showpost.php?p=1498616&postcount=55"!

Zz.

 

[Greenman]

Sorry, I didn't mean to imply it was proof, but rather that *perhaps*? it is a good indication that quantum tunneling on objects such as a tennis ball have a nonzero *possibility*

In other words, that this is a step forward in favor of it being at least possible.

But on another note, I don't know if you got to read my message, but what do you think of Takagi's book on Macroscopic Quantum Tunneling?

 

[ZapperZ]

Sorry, I didn't mean to imply it was proof, but rather that *perhaps*? it is a good indication that quantum tunneling on objects such as a tennis ball have a nonzero *possibility*

In other words, that this is a step forward in favor of it being at least possible.

There is also a non-zero probability mount Everest could spontaneously appear right in front of you, or that a vase broken into a thousand piece could reassemble back into the original vase when you throw the pieces onto the floor. What's your point? When was the last time you saw this happening?

Arguing that something has a "non-zero" probability doesn't mean it will occur.

Zz.

 

[Greenman]

Touché, but I just wonder why so many intellectual people (people who dedicate their life to the respective field) talk about this phenomenon in such depth -

- personally for me what swayed my opinion was Takagi's book, which is why I'm dieing to know what you think of it...I assume you read it?

 

[ZapperZ]

Touché, but I just wonder why so many intellectual people (people who dedicate their life to the respective field) talk about this phenomenon in such depth -

Who?

If anyone tells you that a tennis ball can tunnel through a wall, ask them to show the experimental evidence for it! After all, the Standard Model predicts the existence of the Higgs. We don't just sit here and accept it. We go and hunt for it! This is why this is called physics, and not philosophy! The empirical component of it is necessary.

A tennis ball is a system that is made up of constituents that are not in coherence with each other! Period! Anyone who thinks that such a non-coherent system can actually tunnel together at the same time with equal probability needs to have his/her head examined, or better yet, needs to do some experimental work to have some connection to reality!

- personally for me what swayed my opinion was Takagi's book, which is why I'm dieing to know what you think of it...I assume you read it?

Nope! It would be foolish of me to review something I haven't read. Why do you hold it in such high regards?

Zz.

 

[Greenman]

It's not that they say a tennis ball can tunnel through a wall, but rather that macroscopic quantum tunneling for coherent objects is mathematically possible.

I suggest you read Takagi's book just to see what you think of it. He describes in detail how macroscopic quantum tunneling can be achieved and then provides possible systems for experimental observation of MQT.

He talks about how coherence can be maintained despite environmental factors and measurement issues.

 

[ZapperZ]

It's not that they say a tennis ball can tunnel through a wall, but rather that macroscopic quantum tunneling for coherent objects is mathematically possible.

Coherent object is a different beast. No one is arguing about that. But you are posting in a thread that are asking about a tennis ball! That is what I'm arguing.

The gymnastics that the Delft/Stony Brook experiments had to go through was to get that big, macro particle (10^11 particles) to be in coherence with each other. This is done! One has also done an interference experiments with buckyballs. Again, at very low temperature so that the thermal effects won't destroy the coherence. This is NOT the point of argument.

I suggest you read Takagi's book just to see what you think of it. He describes in detail how macroscopic quantum tunneling can be achieved and then provides possible systems for experimental observation of MQT.

He talks about how coherence can be maintained despite environmental factors and measurement issues.

But why? I mean, if he's saying that coherent object should be able to tunnel as a coherent unit, I'm not contradicting that! What exactly have I posted in this thread that is inconsistent with this?

Zz.

 

[Greenman]

I guess what I was getting at was that if the environment can be altered so as to have cohesion, then a tennis ball *could* go through a wall.

And Takagi describes how such an environment can be achieved and maintained.

Does this make sense?

 

[ZapperZ]

I guess what I was getting at was that if the environment can be altered so as to have cohesion, then a tennis ball *could* go through a wall.

And Takagi describes how such an environment can be achieved and maintained.

Does this make sense?

No.

Zz.

 

[Greenman]

Ok. I'll try to reiterate:

- Takagi describes how to create a cohesive environment.
- Quantum tunneling may occur at the macroscopic scale in a cohesive environment.

Therefore: If the tennis ball and the wall are in this cohesive environment, then quantum tunneling could occur.

Right?

 

[ZapperZ]

Read what I said as being the difference between physics and philosophy. I'm an experimentalist. You'll notice that all of my arguments are based on facts that have been verified experimentally, not just based on theoretical conjecture, or what is "possible".

Zz.

 

[Greenman]

Well, considering this is a theoretical question asking about the theoretical possibility, isn't it valid to answer with a logically-derived theoretical conjecture?

 

[ernestpworrel]

Why would anyone consider the possibility that a tennis ball could tunnel through a wall? QM doesn't even say that. All it says is that there is technically a probabilty of the ball tunneling through the wall, but it also says that there are numerous reasons the ball cannot tunnel through the wall. If you want to break the ball up into individual particles, then each particle has a good chance of tunelling through the wall but there is no real chance that the particles will coalesce into a ball with the same dimensions on the other side of the wall.

 

[ZapperZ]

Well, considering this is a theoretical question asking about the theoretical possibility, isn't it valid to answer with a logically-derived theoretical conjecture?

No, because we will then be back at Mount Everrest being theoretically possible to spontaneously appear in front of your face. After all, one can "logically derive" such a thing as well!

This is why there is such a brouhaha over the LHC and the catastrophic black hole swallowing our universe. People can't put into perspective the SCALE of possibility of things.

Zz.

 

[Greenman]

Yes, but then we go back to the fact that many very very smart people specialized in the subject have written books about the possibility. Books that are used to teach graduate level classes on Quantum Mechanics.

I haven't seen any books describing the math behind or environment needed to see Mount Everest spontaneously imploding on itself.

Surely then, this means there is a clear difference between the two?