Author: haroonkhan

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…

There are very few real-world systems that behave like the simplified mathematical model we used above for a particle in a box. However, recent developments in the nascent field of nanotechnology have made it possible to produce nanostructures of only 2–10 nm in size that exhibit behavior close to the simple particle-in-a-box model we discussed. These tiny structures are…

We learned that |Ψ|2—the square of a system’s wavefunction—is itself a function that gives us the probability of finding a particle at a certain time and position. However, in the simply assigned the fancy symbol |Ψ|2 to the probability of finding a particle at a certain place and at a certain time. For example, in the…