CAMBRIDGEQUANTUM’S
Quantum Software
Development Platform

Version 1.0, November 2021

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What is TKET?
TKET is an advanced software development kit for thecreation and execution of programs for gate-based
quantum computers. It is platform-agnostic, and its
state-of-the-art circuit optimisation routines allow users
to extract as much power as possible from any of today’s
Noisy Intermediate-Scale Quantum (NISQ) devices. TKET
is open source and easily accessible through the PyTKET
Python package, with extension modules providing
compatibility with many quantum computers, classicalsimulators, and popular quantum software libraries.

Optimising circuits
TKET can automatically handle many of the idiosyncrasies
of NISQ devices, lowering the barrier to working withquantum computers. It enables users to build circuits
without worrying about the device architecture, andto use a far larger and more expressive gateset thanavailable natively on any device. As well as reducing
circuit size, TKET also provides tools to reduce noise inNISQ devices and improve overall performance. Thesefeatures free users to focus on their projects and avoidgetting lost in low-level programming.

Across multiple platforms
Today, TKET is enabling our partners, collaborators andclients to effortlessly work across multiple platforms andto tackle some of the most challenging problems infinance, chemistry, material science, AI, and optimisation.

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TKET IS AGNOSTIC TO
THE INPUT LANGUAGE,		 enabling you to		 combine and deploy		 the best solutions.

STATE OF THE ART PERFORMANCEThe toolset enables platform-agnostic
software development and extracts as much
power as possible from Noisy IntermediateScale Quantum (NISQ) devices.

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LANGUAGE-AGNOSTIC MULTIPLE FRONT-ENDSQiskit

Cirq

QuilProjectQ

PyZX

QASM

Quipper

RETARGETABLE • MULTIPLE BACKENDS

Agnosticism

Capabilities

Seamless integration

TKET is platform agnostic, both in the input
language and the target device. It can act as across-compiler, translating programs written
for one platform to a totally different one. This
enables developers and researchers to reuse
software, and easily rerun experiments on new
hardware, with minimal code changes, andwithout sacrificing performance. TKET futureproofs high-level solutions as developers canreact instantly to the availability of newer andbetter quantum hardware. TKET also provides
high-level operations relevant to specificproblems domains, allowing developers to workat a higher level of abstraction, without sacrificing
the ability to target particular systems or devices.

Quantum hardware imposes many restrictions
which require that circuits have a specificform, otherwise they cannot run. Every device
supports only a limited set of quantum gates.
Many devices permit multi-qubit operations
only between specific pairs of qubits, whileothers impose unpredictable performance
penalties if a gate involves the “wrong” qubits.
TKET’s class-leading circuit layout, qubit routing,and gate synthesis routines automaticallyensure that the compiled quantum circuits
adhere to restrictions imposed by the quantum
hardware, and do so with the minimum
performance overhead.

Extension modules are available for interfacing
TKET with a number of popular quantum
software packages, including Qiskit, Cirq,
Pennylane and pyQuil. They target an arrayof devices, including those provided by IBMQ,
Google, Rigetti and Honeywell and utilise
highly optimised classical simulators such as
Stim and Qulacs. A uniform interface connectswith supported backends, allowing for theirseamless insertion into high-level code.

Qermit error mitigation
The simplest way to reduce the impact of noise in aquantum circuit is to reduce the number of quantum
gates in the circuit; therefore TKETs circuit optimisation
methods are an important tool to minimise the impact
of noise when using NISQ hardware. However this is not
the whole story.
Qermit is an open source python module
which implements specially designed error mitigationprotocols which can improve the accuracy of quantum
computations implemented on NISQ devices. These
protocols can improve mean circuit fidelity or give
better estimates of expected values of observables.
Qermit’s composable design allows users to mix andmatch protocols without having to adapt their circuit oralgorithm design.
By virtue of being implemented on the TKET
platform, Qermit may be used with a wide range ofquantum hardware and in conjunction with several
common quantum software development kits.
Qermit seamlessly integrates error mitigation
into experiments built on the TKET platform.

Current protocols
The error mitigation protocols presently available
through Qermit include Zero-Noise Extrapolation,
Probabilistic Error Cancellation, Clifford Data
Regression and State Preparation and Measurement
error correction, as well as a host of others. An
experiment in Qermit is constructed as a data flow graph.
Each vertex represents a sub-process, such as circuit
generation, which is required to run an experiment.
Edges move data between sub-processes and vertices
may be amended to adapt the protocol where necessary.
Graphs and sub-graphs may also be reused in otheroriginal error mitigation protocols. This ensures theextensibility of Qermit, allowing for simple combinationsof error mitigation protocols and the facilitation of new
protocol prototyping.

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Write orimport circuit
Optimisecircuit360 toolkit
TKET is an all encompassing toolkit that enables
you to derive the most value from your preferred
programming frameworks and hardware
platforms. Moreover, TKET is open source andcompletely free to use.

Analyseresults
Map tobackend

Execute onbackend

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TKET’S COMPILATIONROUTINES
AUTOMATICALLYENSURE QUANTUMCIRCUITSCONSTRUCTED
by the user adhere
to restrictions
imposed by thequantum hardware.

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WHY GET STARTEDWITH TKET TODAY?
Open source and completely free to use.
Enables you to extract maximal value from current
and future hardware platforms.
Integrated with all commonly deployed
programming frameworks and hardware
backends.
Multiple features designed to minimise theinfluence of device error.
Provides state-of-the-art circuit optimisation,compilation and error mitigation.
Supported by a rapidly growing community andteam of collaborative experts.

CONTACT US
Please contact our team atEmail: support@cambridgequantum.com

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We set out our vision to positively transform theworld using the power of quantum computing back in
2014. Today, we are recognised as one of the foremost
quantum computing companies, delivering science-led,enterprise-driven solutions to tackle hard problems
across a diverse range of industries.
Cambridge Quantum designs, engineers and deploys
algorithms and enterprise application libraries,
translating cutting-edge research into industry leading
technologies through a product-centric focus. TKET, ourhardware-agnostic software development platform, andother technologies are currently utilised by an expansive
and ever-growing user base.
The team at Cambridge Quantum has been developing
the theoretical foundations of quantum computing
for over 25 years, forging ahead with breakthroughsin the fields of quantum chemistry, quantum artificial
intelligence, quantum cybersecurity and quantum
algorithms.
At present, we have the deepest roster of researchers,
developers and engineers, working to democratisequantum computation and realise the benefits for thegreatest possible number of people.

FOR MORE INFORMATION
LinkedIn
CambridgeQuantum.com

Published by Cambridge Quantum

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