Physics is really bizarre and wonderful. Here I start explaining why the Standard Model has U(1) × SU(2) × SU(3) as its symmetry group. But I don’t assume you know anything about groups or quantum mechanics! So I have to start at the beginning: how the electromagnetic, weak, and strong force are connected to the numbers 1, 2, and 3. It’s all about quunits, qubits and qutrits.
You’ve heard of bits, which describe a binary alternative, like 0 and 1. You’ve probably heard about qubits, which are the quantum version of bits. The weak force is connected to qubits where the 2 choices are called “isospin up” and “isospin down”. The most familiar example is the choice between a proton and a neutron. A better example is the choice between an up quark and a down quark.
The strong f…
Physics is really bizarre and wonderful. Here I start explaining why the Standard Model has U(1) × SU(2) × SU(3) as its symmetry group. But I don’t assume you know anything about groups or quantum mechanics! So I have to start at the beginning: how the electromagnetic, weak, and strong force are connected to the numbers 1, 2, and 3. It’s all about quunits, qubits and qutrits.
You’ve heard of bits, which describe a binary alternative, like 0 and 1. You’ve probably heard about qubits, which are the quantum version of bits. The weak force is connected to qubits where the 2 choices are called “isospin up” and “isospin down”. The most familiar example is the choice between a proton and a neutron. A better example is the choice between an up quark and a down quark.
The strong force is connected to qutrits—the quantum version of a choice between 3 alternatives. In physics these are whimsically called “red”, “green” and “blue”. Quarks come in 3 colors like this.
The electromagnetic force is connected to “quunits” – the quantum version of a choice between just one alternative. It may seem like that’s no choice at all! But quantum mechanics is weird: there’s just one choice, but you can still rotate that choice.
Yes, I know this stuff sounds crazy. But this is how the world actually works. I start explaining it here, and I’ll keep on until it’s all laid out quite precisely.
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