Monday, January 7, 2013

Quantum Algorithms

I've added a few examples to my quantum circuit editor / simulator. The most interesting of which being Grover's Algorithm for unsorted search.

Go ahead and try it out.

Hit "Enter" to evaluate the circuit and get a table of probable outcomes.

The gate F7 makes the fifth qubit in the "|1>" state if the first four qubits are in the state "|0111>" (seven). The circuit is able to determine that "|0111>" is the magic number with over 96% accuracy and only three calls to F7.

I also included an F5 gate. Go ahead and right click those F7 gates away, select the F5 gate, and then drag it into the three places the F7 was. Now it will find "|0101>".

You can save the entire circuit by pressing Ctrl+S. Double click on the GROV, F7, and F5 gates to see what their circuits look like (or to edit them to create your own versions).

Some of the other examples include:

  • Toffoli gate (you can make one simply by dragging to controls onto an X gate, but this is an implementation using only CNots and single-qubit gates)
  • Bell State (the "Hello World" of quantum computing)
  • 2 Qubit QFT and 4 Qubit QFT (again, the editor has it's own quantum fourier transform gate, but these are implementations using only Hadamard gates, controlled rotations, and swaps)
More general info can be found in the help menu on the very top right of the application.