Skip main navigation

Waves

In this video, Rodney Van Meter introduces waves and shows how they move, using a rope as an example.
2.8
Our first task in learning how quantum computers work is to understand the basic nature of waves. We’re all familiar with the waves at the beach and the ripples in a pond. The most basic kind of wave is a sine wave moving through space, a source that wiggles up and down or back and forth is sending out a wave and so anywhere that the wave goes also wiggles up and down or back and forth. Sound in the air, light, radio, microwaves, even the shaking of the ground in an earthquake; they are all waves of one form or another. Let’s look at what happens when we make waves in a rope.
41.1
The distance between two peaks in our wave is called the “wavelength.” The time between two peaks passing a point is called the “period”, and the number of times that peaks pass a point in one second is called the “frequency.” Our frequency with this rope is about two cycles per second, so our period is about half a second. There’s a special type of wave known as a “standing wave.” First, let’s send a wave down our rope. You can see that the wave starts at my end, and when it gets to Satoh’s end of the rope, it turns around and comes back. That reflection is just like light reflecting off of a mirror or an echo reflecting off a mountain.
83.7
If the wave is of a certain frequency and reflects properly, you wind up with a wave that appears to move up and down in place without going anywhere. We can have standing waves that look like halfwave or a whole wave or even higher multiples. Standing waves hold a special place in quantum mechanics and quantum computing. When we get to qubits or quantum bits shortly, if you want, you can think of a qubit as a box with waves in it that holds two different kinds of standing waves. We could for example make the half wave be our zero state and the full wave be our one state. When you study physics, you will spend a lot of time working with waves.
127.4
Both the mathematics and the images are beautiful and result in some unexpected effects. We will study those next.

Our first task in learning how quantum computers work is to understand the basic nature of waves. We are all familiar with the waves at the beach and the ripples in a pond. In this video, we will learn how waves move, and what happens when they reflect.

どのように量子コンピュータが動いているのかということを理解するための最初のステップは、波の基本的な性質を理解することです。海岸の波や池に起こるさざ波を目にすることがあるかと思います。このビデオでは、どのように波が動き、そしてそれらが反射した時どのようなことが起こるのかということについて見ていきます。

This article is from the free online

Understanding Quantum Computers

Created by
FutureLearn - Learning For Life

Our purpose is to transform access to education.

We offer a diverse selection of courses from leading universities and cultural institutions from around the world. These are delivered one step at a time, and are accessible on mobile, tablet and desktop, so you can fit learning around your life.

We believe learning should be an enjoyable, social experience, so our courses offer the opportunity to discuss what you’re learning with others as you go, helping you make fresh discoveries and form new ideas.
You can unlock new opportunities with unlimited access to hundreds of online short courses for a year by subscribing to our Unlimited package. Build your knowledge with top universities and organisations.

Learn more about how FutureLearn is transforming access to education