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This activity teaches a powerful visual method used for writing algorithms (circuits) on quantum computers.
Modern computers are all built to use the same logic and the same assessment criteria to understand each other. Instructions the computers use for achieving tasks are called logic circuits and the result of executing any such circuit will always have just one of the two states: False or True. We can call these two states any way we want, including Asleep and Awake. The building blocks of these circuits are the logic gates and arrangements of logic gates are called circuits. A programmer’s job is to build circuits that expand what computers are able to do: construct circuits that flip between False and True in ways that have not been done before by building more elaborate arrangements of logic gates to construct even more advanced logic circuits. In the activity “Save Schrodinger’s Cat”, the pupils play the role of a programmer that instead of writing code, has a powerful visual method to work with logic gates and create circuits. They will build circuits by placing gates in a sequence to prevent the outcomes given by the Challenge Scenarios from happening to our beloved cat. We want our cat to always be in the Awake (True) state after each challenge scenario. How to get there is completely up to them and their ability to master various logic gates and come up with useful circuits to achieve this goal.
Save Schrödinger’s Cat is about how the logic of quantum mechanical systems is fundamentally different from classical mechanics (the rules most “everyday” physics you encounter follows). The key difference we highlight here is the idea of interference, classically, giving more than one way for something to happen can only increase its likelihood. For example, if you want to know the chances that your jacket will be wet when you come home this evening, you might look at the chance that it will rain, discovering that the neighbour’s sprinkler has also been acting funny and you might get your jacket wet that way, can only increase the chances that you come home wet, never decrease it. Quantum mechanically this is completely different, possibilities can interfere with each other, and adding a new way to get an outcome can reduce the chance of it happening, even to the point where it never happens at all.
Before the activity, the students should know:
After the activity, the students should know:
In the student’s guide, students are asked to complete different challenges using the classic and quantum gates to see if they can arrive at the desired final state. The idea of this experiment is that students start to form ideas about the difference between classical mechanics and quantum mechanics. Before letting students work on the challenges, work with them on the examples provided on the game instructions. Then let them do the initial challenges that only involve classic gates before introducing them into the H and S quantum gates.
This is only part of the Teacher’s Guide. If you have pupils asking about the underlying mathematics of the activity, you can refer to this. In fact, you could use Save Shrödinger’s Cat to get the pupils excited about linear algebra and complex numbers if the time is right. The rules of the game allow you to work with quantum computing using just visual clues, without having to understand the underlying mathematics. However, if pupils are interested in how the mathematics work, here we present what the activity does:
This activity is based on the fundamental rules of play of an educational video game called Quantum Odyssey (available here https://quarksinteractive.com/). Quantum Odyssey is an interactive software meant to make quantum computation an enjoyable experience and to teach people without a background in quantum physics, coding, or linear algebra how to construct real quantum algorithms, using a no code, fully visual and gamified method. The mission behind Quantum Odyssey is explained in this short video https://youtu.be/kvHm0CGcQNo.
Extensions/Alternate Methods for playing: