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Qiskit: a Quantum Information Science Kit

Abby Mitchell

Developer Advocate, IBM Quantum

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Quantum Complexity Theory

BQP

NP

P-Space

NP-Complete

P

P = problems solvable in polynomial time (i.e. efficient for classical computers)

multiplication

NP = problems solvable in non deterministic polynomial time (i.e. easy to check)

NP-Complete = problems solvable in non deterministic polynomial time (i.e. most difficult of the NP class to solve)

BQP = problems solvable in bounded-error quantum polynomial time (i.e. efficient for quantum computers)

Integer factorisation

Simulation of quantum systems

Discrete logarithm

P-Space = problems solvable with a polynomial amount of memory (i.e. space is not the limiting factor)

Does P = NP ?

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Research at IBM Quantum

June 2023 – evidence of quantum “utility”
Simulation of a physics system
Pushing the limits of quantum hardware
Summary: https://research.ibm.com/blog/utility-toward-useful-quantum?sf179077066=1

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Simulating �Quantum Systems

Chemistry

Ground State Energy / Excited State Energy of molecules
Finding new catalysts
Potential energy surfaces

Quantum Dynamics

Condensed matter physics

Material properties
Interaction with light
Magnetic properties
Different phases of matter / phase transitions
Finding new materials

Superconductivity

Fluid dynamics

Batteries

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Solving a problem on a Quantum Computer

Quantum Algorithm

Problem

Quantum Circuits

Compiled Quantum Circuit

Hardware

Simulator

Quantum Tech Stack

The closer you get to the hardware, the more maths/physics you need to know

Problem – e.g. ground state energy of a molecule, max cut problem 🡪 v large maths equation, difficult to compute classically

Quantum algorithm – Variational Quantum Eigensolver, Shor’s Algorithm, Quantum Teleportation

Quantum Circuit – implementing the algorithm in gates/circuits

Compiled Q Circ – compilation - converts your circuit into the appropriate format for the hardware to interpret

Hardware – real qubits

Simulator – emulates real hardware, but is classical (only for small problems)

One way in which this can be done is when we have some function for which we want to determine a global property. For example, if we want to find the value of some parameter xx for which some function f(x)f(x) is a minimum, or the period of the function if f(x)f(x) is periodic. An algorithm on a digital computer might use a process in which f(x)f(x) is computed for a variety of different inputs in order to get sufficient information about the global property. With a quantum computer, however, the fact that we can create superposition states means that the function can be applied to many possible inputs simultaneously. This does not mean that we can access all possible outputs since measurement of such a state simply gives us a single result. However, we can instead seek to induce a quantum interference effect, which will reveal the global property we require.

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Solving a problem on a Quantum Computer

Quantum Algorithm

Problem

Quantum Circuits

Compiled Quantum Circuit

Hardware

Simulator

Quantum Tech Stack

The closer you get to the hardware, the more maths/physics you need to know

Problem – e.g. ground state energy of a molecule, max cut problem 🡪 v large maths equation, difficult to compute classically

Quantum algorithm – Variational Quantum Eigensolver, Shor’s Algorithm, Quantum Teleportation

Quantum Circuit – implementing the algorithm in gates/circuits

Compiled Q Circ – compilation - converts your circuit into the appropriate format for the hardware to interpret

Hardware – real qubits

Simulator – emulates real hardware, but is classical (only for small problems)

NOTE: many people who are using quantum computers aren’t just using it for research into scientific applications of quantum, they are also researching quantum computers themselves. Research into quantum computing is an important scientific field

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ecosystem

research

code

How is Qiskit developed?

IBM

IBM is the biggest driver of functionality and capabilities (and funding!)

IBM has the most advanced devices out there, for qiskit to support the most advanced users of quantum hardware, we need the support of IBM

Research

New research coming out all the time (algorithms, transpilation etc)

Always want to push out features that enable people to do the most cutting edge work they can

Code

Qiskit = compiler

Need the most efficient code out there, don’t want to be the bottleneck

Some of the internals written in rust

Ecosystem

A lot of things get built out by the community that build on top of qiskit

We talk about them in terms of being part of the ecosystem

Could include plugins to different backends like amazon braket, IONq (different hardware types)

Could include research or code that is still a bit experimental

Could include plugins with other traditional science software like pyscf

Sometimes things in the ecosystem can get integrated into qiskit itself

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Qiskit Core

Find a bug & open an issue (even better open a PR!)

Look through open issues (look for good first issue or help wanted tags)

Attend Demo Days and Office hours (qiskit.org/events)

Ecosystem

Contribute to existing projects in the Qiskit Ecosystem (qiskit.org/ecosystem)

Create your own project using Qiskit – and open-source it!

Submit your project to the Qiskit Ecosystem

Translations

Qiskit Localization Contributors can also earn badges at 4 different levels for their translations

Help others

Participate in the Qiskit Slack

Answer Qiskit questions on Quantum Computing StackExchange or StackOverflow

Upvote and comment on GitHub Issues, review others’ PRs

Become a Qiskit Advocate (https://qiskit.org/advocates )

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Q&A

Thank-you!�

(also visit qiskit.org for more info)