Dead or Alive?

Quantum physics generates many profound metaphors that relate to the fundamental functions of the universe and our lives. Imagine a cat within a box that cannot escape. The lid of the box is closed, and there is no possible way of determining the cat's condition--dead or alive--without lifting the lid. This forces the observer to assume that the cat is both alive and dead simultaneously. Fortunately, when the box is open, the cat is alive.

This relates to one of the most bizarre experiments that have been done in quantum physics; it's called the double slit experiment. A physicist, Thomas Young, shot a laser through two narrow slits that landed on a wall behind them. Unexpectedly, the laser created vertical streams of light instead of two beams of light.

For this to happen, light has to be a wave; however, when the slits are a bit wider, the laser creates one stream of light as expected which means light is a particle. In the metaphor, the cat is both alive and dead in the box. The same goes for light; light is both a particle and a wave until observed. Bizarre, light seems to have complete control of it's state; it chooses to be a wave at the quantum level, but also it chooses to be a particle on a larger scale. Why does this happen?

This topic relates more than just to physics; it relates to our lives. We dream of the future; we want to alter the future; we want a pleasant future. However we get caught up in this fourth dimensional lifestyle that we forget about the present. You see, life is full of probabilities. This may happen or that may happen--no guarantee. Instead, you should accept what life throws at you because the most unexpected thing may happen, and that curve ball may hit you in the face. Accept life as it is. Assume that every possibility is equivalent to each other. Prepare yourself for the unexpected. Enjoy life not the dream that may happen.

The Universe is Based on Probability

The quantum world is filled with mystery and wonder. This equation, the Heisenberg Uncertainty Principle, shows probably the most intriguing aspect of quantum physics. In colloquial language, the equation states that there is no possible way to accurately measure a particle's position and momentum at the same time. Now for the mathematics, Δx represents the particles position; Δp, the particle's momentum. The fancy-looking h, ħ, is known as plank's constant which is approximately 6.626 x 10^(-34). To pronounce ħ, say "h-bar." This equation is truly non-intuitive because from the human perspective we can accurately measure an object's velocity, momentum, position, acceleration, and can even predict it's future velocity, momentum, position, etc. by using classical mechanics; however, in the quantum world classical physics breaks down and turns into probability.

Now you may be asking, "why is it so hard to measure these quantities? Don't we have advance microscopes to measure these values?" Firstly, to view an individual particle we need to shed light on it, so it becomes visible. Photons, light particles, can cause a disturbance to the particle's position like when a pool player hits a ball; the ball will accelerate to a different location. Shedding light is equivalent to millions of photons hitting the particle we want to observe. This causes a problem when we look through a microscope. Instead let's just use one individual photon instead of millions to view the particle.When the individual photon bumps the particle, the photon acquires a new direction as well as the particle. So when the photon arrives to the microscope at a new angle, it hits the lens causing it to refract even more (refraction is when light bends). Since we perceive the particle from where the photon is coming from, the measurement is completely inaccurate because of the photon's collision and refraction.

This issue forces us to use probability to locate the individual particle.

This is a probability wave. The probability is measured on the y-axis which is labeled p; the x-axis measures the particle's location which is labeled x. The peaks, or crests, show the highest chances of the particle being at that location. While the bottom peaks, or troughs, show the lowest chances of the particle being there. By using the concept of the derivative, these likely and unlikely possibilities are easy to find (we'll talk about derivatives in a future blog).

That leads us to a question, "is our world governed by probability?" Each human is made up of these infinitesimally small particles, and these same particles have the characteristic of probability. It's like seeing a friend sitting next to you in class, but he can also be sitting across the world in China. Since that probability is extremely low in our perspective, it's almost guaranteed that he or she is sitting next to you. However, having a high probability does not eliminate the other chances. So that very small chance of your friend sitting in china is still plausible. Are we misunderstanding particles' actions? Is there something that controls the universe that deceives us, the observers, to conclude that the universe is based on probability? There has to be something we're missing... I'll leave you with one of my favorite quotes from Einstein.

"God doesn't play dice with the universe." - Albert Einstein