Quantum Mechanics: Unfamiliar Arena of Before & After

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In summary, in The Elegant Universe, Greene describes quantum foam as an unfamiliar arena of the universe where conventional notions of space and time lose their meaning. This is due to the intense warping of both space and time, making it impossible to define concepts like left and right or before and after. This concept may seem counterintuitive and contradictory to thermodynamic laws, but it is a fundamental aspect of quantum mechanics. Greene's statement about before and after losing their meaning refers to the inability to put events in chronological order within a Planck scale time period.
  • #1
Imparcticle
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In the Elegant Universe, on page 129, first paragraph, it says

""...ultramircoscopic examination of space (and time)---it describes an unfamiliar arena of the universe in which the conventional notions of left and right, back and forth (and even of before and after) lose their meaning."

of course, this is illustrating quantum foam.
When Greene says that the meaning of "before and after lose their meaning", does he mean that before and after occur at different times, so to speak? Like, after would happen before before? Of course, that doesn't make any sense at all...but this is quantum mechanics. It doesn't make any [common] sense.
I am sure my understanding of it is incorrect( because it violates laws stated in thermodynamics; Entropy is only in one direction). I would like some clarification please.
 
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  • #2
On first note, I'd would like to say that it is a great book and I hope you have fun with it.

On second not, I think you answered your own question. When you said "space (and time)" I think what you should have said was spacetimeThis is because, while your space is warping heavily (which would explain why the definitions of front, back, and side to side don't apply) so is your time dimension. Time would be warped along with space, both skewing the defintions.

Paden Roder
 
  • #3
But what did Greene mean when he said that notions such as before and after loose their meaning?
 
  • #4
He means that when events occur within a Planck scale time period there is no meanigful way of putting them in chronological order.
 

FAQ: Quantum Mechanics: Unfamiliar Arena of Before & After

What is quantum mechanics?

Quantum mechanics is a branch of physics that deals with the behavior of particles at the subatomic level. It explains how particles such as electrons and photons behave and interact with each other, and how these behaviors can be observed and measured.

How does quantum mechanics differ from classical mechanics?

Classical mechanics describes the behavior of objects on a macroscopic scale, while quantum mechanics deals with the behavior of particles on a microscopic scale. In classical mechanics, objects have definite positions and velocities, whereas in quantum mechanics, particles exist in a state of probability and can be in multiple places at once.

What is the uncertainty principle in quantum mechanics?

The uncertainty principle states that it is impossible to know both the exact position and momentum of a particle at the same time. This is because the act of measuring one property of a particle affects the other, making it impossible to have precise measurements of both properties simultaneously.

How does quantum mechanics relate to time and causality?

In quantum mechanics, time and causality are not always straightforward concepts. The quantum realm operates in a way that allows for particles to exist in multiple states and interact with each other in non-causal ways. This can make it difficult to determine a clear cause-and-effect relationship between events.

How is quantum mechanics being applied in modern technology?

Quantum mechanics has numerous applications in modern technology, including in the development of quantum computers, quantum cryptography, and quantum sensors. It also plays a crucial role in fields such as medicine, materials science, and telecommunications.

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