Quantum Checkers is a game of Checkers demonstrating effects of Quantum Mechanical phenomenon like entanglement, interference and superposition. It is also possible to get a Schrodinger's Cat like situation in the game. The game just doesn't use "randomness" as a special effect(which isn't completely quantum), it is a quantum circuit behaving like a game of checkers. NOTE: This game has been submitted for the IBM Quantum Awards 2019.
Gameplay video: www.youtube.com/watch?v=FklcCPCSuSw
Use the Release to download and run the game. Download and run the QuantumCheckers_setup.exe file. Follow the install instructions. After the setup is complete, you can run the game from QuantumCheckers.exe.
Direct link to Setup: https://github.com/VvenomSsnake/Quantum-Checkers/releases/download/1.0/QuantumCheckers_setup.exe
The goal is to eliminate all your opponent's pieces. Now you have an advantage of making a quantum move, which move your piece with 50% probability. A measurement can be forced on a piece during an attempted capture, or a standard move, revealing it's position. Each square is a qubit in the IBMQ Qiskit simulator. You can also create Schrodinger's cat like pieces, both Alive and Dead.
Quantum mechanics is not intuitive, even for the people who understand it's math, since we do not experience quantum effects in our daily lives on a macroscopic level. We do however, understand and learn how to ride a bicycle, balancing and tilting it, without even knowing the math. Video games provide a platform for building intuition about stuff that we do not experience in our daily lives. Simple games like tic-tac-toe, chess, and checkers that require strategy, can help explore the weird world of quantum mechanics while enjoying the game.
The game runs on Unreal Engine 4 using Qiskit-Python as a tool for generating quantum effects. The UnrealEnginePython plugin is used to help Unreal Engine communicate with the Python program. The python program creates a 32 qubit circuit, one qubit for each square. With each move, a corresponding gate is applied to the respective qubits. A measurement takes pplace collapsing the state of the all associated qubits, when trying to move to a square which is in some kind of superposition.
An embedded version of python with Qiskit and Numpy is needed to play this, all are included in the release.
The game can also be directly played from inside Unreal Engine 4.22 (higher versions not supported by UnrealEnginePython plugin)
Each square represents a qubit. The states |0> and |1> correspond to an empty square and a piece being on the square respectively. Here's an example with two qubits.
A unitary is applied in each move, with some classical logic happening in the UnrealEngine separate from the circuit during the captures.
When you make a normal move, an iswap gate is applied to the corresponding qubits.
When you make a quantum move, the square root of iswap is applied. The goal is to have a gate that would create a superposition between the |10> and |01> states. The iswap has been chosen for demonstrating interference.
A capture implements a three piece measurement decision tree in the UnrealEngine, and resets the qubit corresponding to the captured piece back to 0, if it measured to be there. This might create a half dead half alive piece.