Quantum Cosmology - Imaginary Time

[putongren]

I have trouble understanding the concept of imaginary time. As I understand it (by reading other online sources), imaginary time was developed by Stephen Hawking and Hartle in their theory of quantum cosmology. Quantum cosmology is applying quantum mechanical principles to cosmology as a whole, so the concept of the wave function is applied to the universe as a whole. There are infinite number of parallel universes as a consequence of applying the wave function to the universe. Also, an application of imaginary time can be found in quantum tunneling. When a particle is in the process of quantum tunneling, it is said to be in imaginary time. There are other technical terms I encountered during my reading such as Wick's rotation and Sum Over History Path Integral which I wasn't able to understand. Is my understanding of this topic accurate at all? Is there more to the story than this?

 

[azntoon]

Imaginary time is indeed a concept developed by Stephen Hawking and Hartle in their theory of quantum cosmology. It is related to the idea of a quantum wave function applied to the universe as a whole, which suggests that there are an infinite number of parallel universes. In this framework, imaginary time (also known as Euclidean time) is used to calculate probabilities for different outcomes in the universe. This is often referred to as the Sum Over Histories Path Integral, and it involves a Wick's rotation, which is a mathematical transformation that converts physical time into imaginary time.It is important to note that imaginary time is not a real "time" that can be experienced or measured in our physical universe. Instead, it is a mathematical tool used to understand quantum mechanics and cosmology. In quantum tunneling, particles are said to be in imaginary time because they are transitioning between states without spending any "real" time in between them.In summary, imaginary time is a concept developed in quantum cosmology that involves using a mathematical tool called Wick's rotation to convert physical time into imaginary time in order to calculate probabilities for different outcomes in the universe. It is not a real "time" that can be experienced or measured, but rather a mathematical tool used to understand quantum mechanics and cosmology.