DescriptionQ-Sim is a simulator for a 5-qubit quantum computer, based heavily off of IBM's QX.
It supports all the same logical operations as IBM's QX as well as supporting programs written in QASM.
There are a few example programs:
"QSDC.QASM"
- Demonstrates the algorithm for a quantum superdense coding.
"BELL.QASM"
- Sets up a Bell state of entangled qubits.
"CNOTR.QASM"
- Uses Hadamard gates to reverse the CNOT gate.
"SWAP.QASM"
- Uses several Hadamard and CNOT gates to create a SWAP gate.
"ADD.QASM"
- Constructs a half-adder from a Toffoli gate and a CNOT gate according to this paper.
I apologize for the really low quality screenshots, I will update them once SmileBASIC finally gives us that screenshot update...
Update 1:
- Added native SWAP gate, Toffoli gate, and Fredkin gate
- Bug fixes
- CNOT gates can have their direction swapped
- Hold the L button while starting a program will allow you to set the initial state of all 5 qubits (type in something such as "00110")

6 Comment(s)amihartI recently came up with a much better algorithm for simulating quantum logic operations, I will eventually come back to update this. Currently I have it implemented in an Android/PC app I am working on here. I also detailed the algorithm on StackExchange here (my answer is the second one).RGamesOfficalIntermediate ProgrammerI can make programs, but I still have trouble here and there. Programming StrengthMinecraft Is Awesome!I love Minecraft!Express YourselfVideo GamesI like to play video games!HobbiesThis proves that you don't need a Quantum ComputerMakkyAvatar TabooI didn't change my avatar for 180 daysWebsiteExpert ProgrammerProgramming no longer gives me any trouble. Come to me for help, if you like!Programming StrengthNight PersonI like the quiet night and sleep late.Express Yourselflmao, sure...
sarcasm existsamihartYou can't simply apply a logic gate to 1 qubit at a time because qubits can become entangled with each other, so instead you apply the logic gate to the entire system at once, which is represented as a 2^n by 2^n matrix where n is the number of qubits you have in memory. This means if you were trying to simulate a machine with 250 qubits of memory, you're looking at having to construct a matrix of 2^250 by 2^250 complex numbers in order to simulate it. A matrix this large would have more elements in a single row than there are atoms in the observable universe. This is why the world record for the number of qubits simulated is only 46. Simulating 1-10 qubits is easy, but its complexity grows exponentially. Having a real quantum computer would allow you to do these operations in a single iteration. This is just a toy to help you understand quantum computers inspired by IBM's Quantum Experience. It cannot replace quantum computers. Trying to perform a quantum algorithm in a classical simulation is incredibly slow. You need a real quantum computer to get the benefits. bluekrillIntermediate ProgrammerI can make programs, but I still have trouble here and there. Programming StrengthDrawingI like to draw!HobbiesVideo GamesI like to play video games!HobbiesA simulation is not equivalent in performance or accuracy to the real thing.RGamesOfficalIntermediate ProgrammerI can make programs, but I still have trouble here and there. Programming StrengthMinecraft Is Awesome!I love Minecraft!Express YourselfVideo GamesI like to play video games!HobbiesIt may not be close, but its fast.

~~sarcasm exists~~