Category: Schrodinger (And His Zombie Cat)

Let’s now see how we would actually go about determining the leg of the interferometer taken by a photon. Let’s insert a third polarizer between the output of beam splitter 2 and the ground glass screen, as shown in Figure 134b. This polarizer is the equivalent of the analyzing polarizer of Figure 121. At an angle of…

Just as with the two-slit experiments, the Mach–Zehnder interferometer builds up an interference pattern even when shooting photons one at a time. Remember that we also learned that Tonomura was able to do the same thing using single electrons, and more recently the team at the University of Vienna demonstrated two-slit interference using a collimated…

Let’s now complicate the setup just a tiny bit, as shown in Figure 129. Here, photons are split just as before by a first beam splitter into T and R photons. Each of these are then reflected 90° so they will meet at a second beam splitter. Trace the possible paths of the photons and you…

Beam splitters can be classified according to the mechanism used to split the incident light beam. As shown in Figure 127a, some beam splitters are made by depositing reflective elements over a transparent substrate. The reflective elements could be fully reflective mirrors arranged in a polka-dot pattern or fine metallic particles dispersed in a random manner.…

Another way in which physicists commonly prepare quantum states is by using partial reflectors as a way of placing a photon in a superposition of states at two different positions. Look out at night through any window in your house and you are essentially looking through a beam splitter. This is because you can see light…

It is very important to remember that Schrödinger’s cat thought experiment was proposed as an absurd extrapolation of the Copenhagen Interpretation. Although we are ignorant about the boundary between quantum and classical systems, quantum physics has very little to do with cats or any other macroscopic system. For all of the reasons that we have…

The leading alternative interpretation was developed in 1957 by American physicist Hugh Everett, who proposed that the universe splits every time there’s an event with more than one possible outcome. Each different universe evolves with one of the possibilities realized. As shown in Figure 120, the bizarre, but logically consistent Many-Worlds Theory interprets the Schrödinger cat thought experiment…

Let’s revisit the original particle-in-a-box problem (Figure 109). We had assumed that the system had a specific energy that did not vary with time. This allowed us to use a simple form of Schrödinger’s equation that gave us the wavefunctions of the system that depend only on the position x within the box, and the system’s quantum…

An interesting question to ask is: what is the time that tunneling particles spend inside the barrier? The experimental setup to demonstrate photon tunneling can be modified, as shown in Figure 117, to measure the total tunneling time of the photons, that is tv + th. This strange, two-part timing is due to the nature of frustrated total internal…

chSo far, our analysis of the particle-in-a-box problem has assumed that the barriers around the box are infinite: which allowed us to force the particle to always be within the box. We were thus able to make Ψ = 0 for x ≤ 0 and x ≥ L. What would happen if the walls didn’t have infinite potential? Well, the…