Greetings
Mathematically speaking (in theory), zero point energy is attainable. It can be measured. But man has not been able to create a practical device to extract the usable energy.

So we are now discussing what is proven mathematically and what is practically attained from that mathematical proof. According to quantum physics, Einstein's theory of relativity is valid. Einstein proposed that man could travel through time. But practically, there is no way for man's body to travel at the speed of light.

According to the theory of relativity, there is never a physically distinguishable state of motion which may be called "absolute rest". So you are correct that absolute zero does not completely stop the motion of molecules.

There is usually an issue of degradation (percent error) when going from theory to practical, even if it is almost unmeasureble on a nano scale.

In Calculus, we used imaginary numbers signified by "i", which is the square root of -1. Now do imaginary numbers really exists or are they used to explain something that is not able to be obtained by conventional mathematical overstanding?

Otherwise, the equation X^2(squared) + 1 = 0, could not be solved. It can be graphed as a parabola but we cant use real numbers to solve it on paper.

When u take calculus, you will gain a different perspective on mathematics and its balancing act.

"In physics, the zero-point energy is the lowest possible energy that a quantum mechanical physical system may possess; it is the energy of the ground state of the system. All quantum mechanical systems have zero probability of finding system at zero energy, thus the energy of the lowest state is not equal to zero (thus this energy is called zero point energy). The term can be explained on the example of simplest quantum system - oscillator (quantum harmonic oscillator). In quantum field theory, it is a synonym for the vacuum energy, an amount of energy associated with the vacuum of empty space. - energy of virtual particles. In cosmology, the vacuum energy is taken to be the origin of the cosmological constant. Experimentally, the zero-point energy of the vacuum leads directly to the Casimir effect, and is directly observable and measurable in nanoscale devices made of conductors.

The concept of zero-point energy, and the hint of a possibility of extracting "free energy" from the vacuum, has attracted the attention of amateur inventors, despite that quantum mechanics explicitly prohibits transitions from lowest state to any lower state (because there is none). As of 2006, there is no known practical method to extract usable energy from the vacuum, although mainstream research is being carried out by the Calphysics Institute, NASA's Glenn Research Center, and aerospace giant BAE Systems."

***taken from wikipedia.com