Can someone explain quantum fluctuation to me?

Question

Im curious because i heard this quote somewhere:

"Some cosmologists believe that the universe was created out of "nothing" via a quantum fluctuation."

Is this quote true? What exactly is a quantum fluctuation?

Answer 1

They say the early universe was molded by quantum fluctuation to create the universe we see today.

http://en.wikipedia.org/wiki/WMAP

In quantum physics, a quantum fluctuation is the temporary change in the amount of energy in a point in space, arising from Werner Heisenberg's uncertainty principle.

That means that conservation of energy can appear to be violated, but only for small times. This allows the creation of particle-antiparticle pairs of virtual particles. The effects of these particles are measurable, for example, in the effective charge of the electron, different from its "naked" charge.

In the modern view, energy is always conserved, but the eigenstates of the Hamiltonian (energy observable) aren't the same as (e.g.the Hamiltonian doesn't commute with) the particle number operators.

Quantum fluctuations may have been very important in the origin of the structure of the universe: according to the model of inflation the ones that existed when inflation began were amplified and formed the seed of all current observed structure.

Quantum fluctuations are also related to virtual particles which are particles that exists for a limited time and space, introducing uncertainty in their energy and momentum due to the Heisenberg Uncertainty Principle. (Indeed, because energy and momentum in quantum mechanics are time and space derivative operators, then due to Fourier transforms their spans are inversely proportional to time duration and position spans, respectively).

Virtual particles exhibit some of the phenomena that real particles do, such as obedience to the conservation laws. If a single particle is detected, then the consequences of its existence are prolonged to such a degree that it cannot be virtual. Virtual particles are viewed as the quanta that describe fields of the basic force interactions, which cannot be described in terms of real particles. Examples of these are static force fields, such as a simple electric or magnetic fields, or any field that exists without excitations that result in its carrying information from place to place.

The virtual particles come into and out of existance in a vacuum state is the quantum state with the lowest possible energy. Generally, it contains no physical particles. The term "zero-point field" is sometimes used as a synonym for the vacuum state of an individual quantized field.

According to present-day understanding of what is called the vacuum state or the quantum vacuum, it is "by no means a simple empty space", and again: "it is a mistake to think of any physical vacuum as some absolutely empty void." According to quantum mechanics, the vacuum state is not truly empty but instead contains fleeting electromagnetic waves and particles that pop into and out of existence.

Answer 2

I can not make sense out of this without assuming the existence of at least one spatial dimension.

What we know of quantum fluctuation occurs because of the application of Heisenberg's uncertainty principle.

Quantum fluctuation is said to manifest in virtual particle pairs (virtual because it has "borrowed" energy form the intrinsic qualities of the universe in order to exist) matter and anti-matter they exist briefly and then annihilate each other shortly after existence.

Maybe I do not know enough about physics, but to me the theory of quantum fluctuation to explain the origin of the universe is weak because.

A. How does quantum fluctuation occur if there is no space time

B. How did matter come to survive a quantum fluctuation event where equal parts anti-matter should have canceled out the existence of the universe?

I have found some work concerning B but I have not with A so essentially you are left with the same question, where did the spatial dimension come from?

Of course it might be a paradox because quantum uncertainity applies to order of events with regards to time as a consequence of special relativity and how space time are intertwined.

Answer 3

Jim Albrecht, who lived in Sydney Australia in 1964, is an expert on this.