# Qadence A framework for experimenting with analog/digital quantum computing David 'Yoric' Teller ![](../img/pasqal.png)
# Qadence A framework for experimenting with analog/digital quantum computing David 'Yoric' Teller ![](../img/pasqal.png) (not my work)
# About Pasqal - We build qubits!
# About Pasqal - We build qubits! - Quantum computers - Quantum algorithms - Quantum tools - Quantum teaching materials - ...
![photo of Pasqal's quantum computer showing lasers and lenses](../img/qpu.jpg)
# Quantum computing? - Compute with qubits, not bits. - Still very much open research.
# Quantum computing? - Compute with qubits, not bits. - Still very much open research. - Hardware - Algorithms - Compilers & tools
# Quantum computing? - Compute with qubits, not bits. - Still very much open research. - Hardware - Algorithms - Compilers & tools - Hype
# Why quantum? - Today's processors fight quantum physics. - Aiming for the next generation(s) of hardware.
# Why quantum? - Today's processors fight quantum physics. - Embrace it! - Aiming for the next generation(s) of hardware.
# Why quantum? - Today's processors fight quantum physics. - Aiming for the next generation(s) of hardware. - Faster? - Much more energy-efficient?
# Why quantum? - Today's processors fight quantum physics. - Aiming for the next generation(s) of hardware. - Also, get out of the current hardware dead end.
# Why quantum? - Today's processors fight quantum physics. - Aiming for the next generation(s) of hardware. - Also, hype.
# Bits ![a bit (represented as a square signal)](../img/signal.png)
# Qubits ![a qubit (represented as a unitary sphere)](../img/sphere.png)
# Two flavours - Digital - Analog
# Digital ![example of a digital circuit](../img/digital.svg)
# Digital - A program is a _circuit_. - Programming languages exist.
# Digital - A program is a _circuit_. - Programming languages exist. - ... for model hardware.
# Analog ![the pasqal logo made from individual atoms](../img/register.png)
# Analog - A program is geometry + pulses. - Maps naturally to hardware constraints.
# Analog - A program is geometry + pulses. - Maps naturally to hardware constraints. - ...and to some classes of problems.
# Analog - A program is geometry + pulses. - Maps naturally to hardware constraints. - ... how do you program _that_?
# Analog ![\hat{H}(\Omega, \delta, \phi; t) = \sum_{\text{atom } i}\left( \overbrace{ \frac{\Omega}{2}\left[\cos(\phi) \hat \sigma^x_i - \sin(\phi) \hat \sigma^y_i \right] - \delta \hat n_i }^\text{Programmable laser pulse, global interaction} + \underbrace{\sum_{j
# Analog - A program is geometry + pulses. - Maps naturally to hardware constraints. - ... how do you program _that_? - no, really?
# Qadence
# Qadence A toolkit designed to: - experiment with Digital + Analog circuits; - simulate or execute circuits;
# Qadence A toolkit designed to: - experiment with Digital + Analog circuits; - learn how to design a hardware-friendly language; - without dealing with laser pulses. - simulate or execute circuits;
# Qadence A toolkit designed to: - experiment with Digital + Analog circuits; - simulate or execute circuits; - _optimize_ circuits wrt constraints.
# Qadence A toolkit designed to: - experiment with Digital + Analog circuits; - simulate or execute circuits; - still not my work 😅.
# Demo time! - [Digital](http://localhost:8888/notebooks/Qadence%20digital.ipynb) - [Solving a problem](http://localhost:8888/notebooks/Qadence%20MaxCut.ipynb) - [Analog](http://localhost:8888/notebooks/Qadence%20analog.ipynb) - [Solving a problem](http://localhost:8888/notebooks/Qadence%20curve%20fitting.ipynb)
# Conclusions
# Summary - A toolkit for exploring quantum circuit design. - On current hardware. - On hypothetical hardware. - Circuit optimization. - Not a programming language.
# Summary - A toolkit for exploring quantum circuit design. - On current hardware. - On hypothetical hardware. - Circuit optimization. - Not a programming language - ...yet
# Future works - Libraries - Domain/algorithm enrichments - Compilation - Reconfigurable registers. - Arbitrary Hamiltonians. - Towards easier programming
# Thanks Actual work by Aleksander Wennersteen, Dominik Seitz, Niklas Heim, João P. Moutinho, Roland Guichard, Vytautas Abramavicius, Gert-Jan Both, Gergana V. Velikova, Anton Quelle, Caroline de Groot, Mario Dagrada, Vincent E. Elfving
@pasqal.com - https://pasqal-io.github.io/qadence - https://browse.arxiv.org/abs/2401.09915