OpenQASM

Last updated
OpenQASM
Stable release
3.1.0 / May 15, 2024;13 months ago (2024-05-15)
Implementation language Python
License Apache License 2.0
Filename extensions .qasm
Website openqasm.com

Open Quantum Assembly Language (OpenQASM; pronounced open kazm) [1] is a programming language designed for describing quantum circuits and algorithms for execution on quantum computers.

Contents

Language

It is designed to be an intermediate representation that can be used by higher-level compilers to communicate with quantum hardware, and allows for the description of a wide range of quantum operations, as well as classical feed-forward flow control based on measurement outcomes.

The language includes a mechanism for describing explicit timing of instructions, and allows for the attachment of low-level definitions to gates for tasks such as calibration. [1] OpenQASM is not intended for general-purpose classical computation, and hardware implementations of the language may not support the full range of data manipulation described in the specification. Compilers for OpenQASM are expected to support a wide range of classical operations for compile-time constants, but the support for these operations on runtime values may vary between implementations. [2]

The language was first described in a paper published in July 2017, [1] and a reference source code implementation was released as part of IBM's Quantum Information Software Kit (Qiskit) for use with their IBM Quantum Experience cloud quantum computing platform. [3] The language has similar qualities to traditional hardware description languages such as Verilog.

OpenQASM defines its version at the head of a source file as a number, as in the declaration:

OPENQASM3;

The level of OpenQASM's original published implementations is OpenQASM 2.0. Version 3.0 of the specification is the current one and can be viewed at the OpenQASM repository on GitHub. [4]

Examples

The following is an example of OpenQASM source code from the official library. The program adds two four-bit numbers. [5]

/* * quantum ripple-carry adder * Cuccaro et al, quant-ph/0410184 */OPENQASM3;include"stdgates.inc";gatemajoritya,b,c{cxc,b;cxc,a;ccxa,b,c;}gateunmaja,b,c{ccxa,b,c;cxc,a;cxa,b;}qubit[1]cin;qubit[4]a;qubit[4]b;qubit[1]cout;bit[5]ans;uint[4]a_in=1;// a = 0001uint[4]b_in=15;// b = 1111// initialize qubitsresetcin;reseta;resetb;resetcout;// set input statesforiin[0:3]{if(bool(a_in[i]))xa[i];if(bool(b_in[i]))xb[i];}// add a to b, storing result in bmajoritycin[0],b[0],a[0];foriin[0:2]{majoritya[i],b[i+1],a[i+1];}cxa[3],cout[0];foriin[2:-1:0]{unmaja[i],b[i+1],a[i+1];}unmajcin[0],b[0],a[0];measureb[0:3]->ans[0:3];measurecout[0]->ans[4];

See also

References

  1. 1 2 3 Cross, Andrew W.; Bishop, Lev S.; Smolin, John A.; Gambetta, Jay M. (2017). "Open Quantum Assembly Language". arXiv: 1707.03429 [quant-ph].
  2. "OpenQASM Live Specification" . Retrieved 26 December 2022.
  3. qiskit-openqasm: OpenQASM specification, International Business Machines, 4 July 2017, retrieved 6 July 2017
  4. https://github.com/openqasm/openqasm OpenQASM
  5. "openqasm/adder.qasm at master · openqasm/openqasm · GitHub". GitHub . 29 January 2022.