RSS icon
Twitter icon
Facebook icon
Vimeo icon
YouTube icon

Quantum circuits for quantum operations

September 7, 2016 - 11:00am
Roger Colbeck
U. York

Every quantum gate can be decomposed into a sequence of single-qubit gates and controlled-NOTs. In many implementations, single-qubit gates are relatively 'cheap' to perform compared to C-NOTs (for instance, being less susceptible to noise), and hence it is desirable to minimize the number of C-NOT gates required to implement a circuit.

I will consider the task of constructing a generic isometry from m qubits to n qubits, while trying to minimize the number of C-NOT gates required.  I will show a lower bound and then give an explicit gate decomposition that gets within a factor of about two of this bound.
Through Stinespring's theorem this points to a C-NOT-efficient way to perform an arbitrary quantum operation.  I will then discuss the case of quantum operations in more detail.

CSS 3100A

Subscribe to A Quantum Bit 

Quantum physics began with revolutionary discoveries in the early twentieth century and continues to be central in today’s physics research. Learn about quantum physics, bit by bit. From definitions to the latest research, this is your portal. Subscribe to receive regular emails from the quantum world. Previous Issues...

Sign Up Now

Sign up to receive A Quantum Bit in your email!

 Have an idea for A Quantum Bit? Submit your suggestions to