Discussion about quantum mechanics and spacetime

In summary, during the conversation, it was discussed that special relativity suggests time is not a fundamental aspect of reality, but rather a dynamical phenomenon that is dependent on events and can fluctuate. Professor Gross also shared his belief that the metric of spacetime is a fluctuating object and that a theory of quantum gravity is needed to fully understand it.
  • #1
docnet
Gold Member
676
319
TL;DR Summary
In the Interview called Closer To Truth: What's Real About Time? The Nobel laureate physicist David J Gross said that the metric of space time is a dynamical and quantum mechanical fluctuating object.
Robert Lawrence Kuhn:

It seems that special relativity suggests time is like gravity and electromagnetism, not built into the absolute fabric of reality like logic and causation.

David J Gross:

Yes, time is dynamical. The phenomena are dynamical and are labeled by what we call time. Including the time difference between events, what we call the metric of space time is a dynamical and indeed quantum mechanical fluctuating object. We tend to think of time as evolving. one of the strangest notions is the feeling we have of present moving, as if somehow reality consisted of the universe at a given time, observer dependent according as it may be according to Einstein, moving forward.

The interview

My Question: What did professor Gross mean when he said that the metric of spacetime is a fluctuating object? I assumed how we define time depends on the time difference between physical events, which are quantum mechanical and fluctuating. I did not know much about this topic and wanted to hear physical examples if anyone felt like explaining them.
 
  • Like
Likes vanhees71
Physics news on Phys.org
  • #2
docnet said:
What did professor Gross mean when he said that the metric of spacetime is a fluctuating object?
He means that he believes General Relativity, the classical theory of the metric of spacetime, is not a fundamental theory; that we will need to find a theory of quantum gravity that is more fundamental, and from which GR emerges as a classical approximation the way that other classical theories (such as classical electrodynamics) emerge as approximations to underlying quantum theories.

It should be noted that we have no evidence of any quantum aspects of gravity or the metric of spacetime, so this statement by Gross is not a statement of a scientifically known fact, but a statement of his opinion. His opinion is widely shared among physicists, but it's still an opinion, not a fact.
 
  • Like
Likes vanhees71 and docnet

1. What is quantum mechanics?

Quantum mechanics is a branch of physics that studies the behavior of matter and energy at a very small scale, such as atoms and subatomic particles. It explains how particles interact with each other and how they behave in different situations.

2. How does quantum mechanics relate to spacetime?

Quantum mechanics and spacetime are both fundamental concepts in modern physics. Quantum mechanics describes the behavior of particles at a very small scale, while spacetime is the fabric of the universe that describes how objects move and interact in the larger scale. Some theories, such as quantum field theory, combine both quantum mechanics and spacetime to explain the behavior of particles in the universe.

3. What is the uncertainty principle in quantum mechanics?

The uncertainty principle is a fundamental principle in quantum mechanics that states that it is impossible to know both the position and momentum of a particle simultaneously with absolute certainty. This means that the more precisely we know the position of a particle, the less we know about its momentum, and vice versa.

4. How does quantum mechanics challenge our understanding of reality?

Quantum mechanics challenges our understanding of reality because it introduces the concept of probability and uncertainty in the behavior of particles. In classical mechanics, the behavior of objects is deterministic, meaning that their future states can be predicted with certainty. However, in quantum mechanics, the behavior of particles is described by probabilities, and their exact states cannot be predicted with certainty.

5. What are some real-life applications of quantum mechanics?

Quantum mechanics has many practical applications in modern technology, such as in the development of transistors, lasers, and computer memory. It also plays a crucial role in fields such as chemistry, materials science, and quantum computing. Additionally, quantum mechanics has led to advancements in medical imaging and cryptography.

Similar threads

Replies
6
Views
668
  • Quantum Physics
Replies
15
Views
2K
Replies
12
Views
687
Replies
21
Views
938
Replies
12
Views
1K
  • Quantum Physics
Replies
22
Views
972
Replies
8
Views
1K
  • Quantum Physics
Replies
27
Views
2K
Replies
10
Views
2K
Replies
1
Views
563
Back
Top