# 'Genuine Decoherence' and Macroscopic Superposition

• StevieTNZ
In summary, genuine decoherence refers to the collapse of the wave function in a theory and its mathematical equations. This occurs when a micro system interacts with a macroscopic apparatus and a definite state appears for both. For genuine decoherence to be predicted in a future theory, it may need to allow for macroscopic superpositions, even if they only last for a short time. However, current quantum mechanics formalism can also incorporate hidden variables to solve the measurement problem. Decoherence states that macroscopic superpositions will quickly resolve into mixed states, similar to how a tossed coin will quickly result in either heads or tails. This differs from collapse interpretations, where a macroscopic superposition can persist until an observation causes a collapse.
StevieTNZ
By 'Genuine Decoherence' - I mean collapse of the wave function by a theory and its mathematical equations.

If a micro system encounters a macroscopic apparatus - in collapse theories a definite state appears for both the apparatus and system, but after a tiny time since the system entangled with the apparatus.

For genuine decoherence to occur and be predicted in a future theory, does it need to allow macroscopic superpositions (even if they last for a short time)?

Of course we can keep current QM formalism and have hidden variables to remove the measurement problem.

Decoherence says that macroscopic superpositions will very quickly resolve themselves into mixed states - Schrödinger's cat wiil very quickly decohere from a macroscopic superposition of dead and alive to a mixed state in which the cat is either dead or alive as surely as a tossed coin is heads or tails.

Thus decoherence doesn't preclude macroscopic superpositions, it just says they don't last very long. This differs from collapse interpretations in which a macroscopic superposition (Schrödinger's both dead and alive cat, for example) can persist until an observation forces the collapse.

## 1. What is 'genuine decoherence'?

'Genuine decoherence' refers to the process by which a quantum system loses its coherence, or the ability to exist in multiple states at once, due to interactions with its environment. This results in the system behaving classically, with definite and distinguishable states.

## 2. What is macroscopic superposition?

Macroscopic superposition is the state in which a macroscopic object, such as a particle or molecule, exists in multiple states simultaneously. This is a consequence of quantum mechanics and is usually only observed in small, isolated systems.

## 3. How does 'genuine decoherence' affect macroscopic superposition?

'Genuine decoherence' leads to the loss of macroscopic superposition, as the system becomes entangled with its environment and behaves classically. Without isolation from the environment, macroscopic superposition is not sustainable.

## 4. Can macroscopic superposition be observed in everyday objects?

No, macroscopic superposition is only observed in isolated systems at very low temperatures. The larger and more complex an object is, the more difficult it is to isolate it from its environment and observe quantum effects.

## 5. How does understanding 'genuine decoherence' and macroscopic superposition impact technology?

Understanding these concepts is crucial for the development of quantum technologies, such as quantum computing and quantum cryptography. It also sheds light on the boundary between the classical and quantum worlds, and helps us better understand the fundamental nature of reality.

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