Relational Quantum Mechanics
Chapter 1 - Worldview
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Welcome to the Relational Quantum Mechanics page
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For the second part of the first building block, reality (building on the relationship between time and space), we look at the most minor elements of our reality on this page.
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Core ideas
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Relationships create reality
Relational Quantum Mechanics, in general terms, is not as difficult as it may seem. It's a principle that, once broken down, is quite straightforward and within your grasp to understand.
- Imagine you're in a forest, and you close your eyes. Do the trees disappear? No, they're still there, their particles interacting with all the other particles in the forest. This relatable scenario is a simple illustration of Relational Quantum Mechanics.
- But when no one is in the woods, and a tree falls, does it make a noise? In this case, no, the wave particles only interact with other wave particles in the air. They don't interact with a particle that is a part of a 'hearing mechanism'.
These simple examples illustrate Relational Quantum Mechanics, a theory postulated by Carlo Rovell:
- A system has one state relative to a given observer and a different state relative to another observer
- An observable has one value relative to one observer and a different value relative to another observer
The statements above mean that we live in a reality related to ourselves, even at the most fundamental level.
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Carlo Rovelli
- Why do we remember the past but not the future?
- Why is it that we can decide what to do tomorrow but not what we did yesterday?
Theoretical physicist Carlo Rovelli revels in asking such questions about the nature of time. They might seem trivial at first, but they force one to look deeper, revealing new aspects of reality. In the world of physics, Rovelli is known for his work on loop quantum gravity—a theory that builds on Einstein’s general relativity and seeks to understand the quantum aspects of spacetime. The theory shows that the fabric of spacetime is woven by tiny loops built into a network.
“The quest for quantum gravity is to ask what time and space are. The main result, which took so long to develop, is that if you take general relativity, apply quantum mechanics, and calculate, what comes out is the granularity of space — there is no continuous space."
“Studying quantum mechanics is about relationships, systems, structures, and orders that make the world,” says Rovelli. Meaning is created in relation to surroundings and is not inherent in individual things.
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| Santa Fe Institute - 2024 |
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Deep dive
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Elements of physics
Relativity, complementary, symmetry, and invariance form the heart of modern physics. Let us examine it from the viewpoint of a painter.
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Relativity is the idea that the same subject can be faithfully and without loss represented in different ways. For example, we can paint the same scene from many different perspectives. The dispositions of paint on the canvas will be different. But all will represent the same information about the subject, just differently encoded.
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Complementarity is a principle that builds on relativity. It suggests that many different views of a subject can be equally valid. However, when it comes to painting, observing, or describing the subject, you must choose a specific perspective.
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Symmetry , a concept closely linked to relativity, shifts the focus from the viewer to the subject. Imagine rotating the subject of a painting. From any fixed perspective, it will appear different. However, its projective description, the totality of views from all possible perspective rotations, remains unchanged. This rotation of the object is a symmetry of its projective description. It's like changing the object by rotating it, without actually altering its projective description. This is the essence of symmetry.
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Invariance is the counterpoint to relativity. Many aspects of the subject will be differently represented as we change perspectives. However, some features are standard to all those representations. For example straight lines in the painting will always appear as straight lines from any perspective. Features that are common to all representations are said to be invariant. Invariant quantities are profoundly important, because they define features of the subject that are valid from any perspective.
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| A beauiful question - Frank Wilczek - Penguin Books - 2013 |
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