Korbinian Kottmann
@qottmann.bsky.social
Quantum compilation & open source software.
working on pennylane.ai
https://github.com/qottmann
free hot takes
working on pennylane.ai
https://github.com/qottmann
free hot takes
It is that time of year again! The @unitary.foundation qOSS survey is here! Please consider filling it out if you are using, developing or maintaining any quantum OSS like @pennylaneai.bsky.social or similar
unitary.foundation/posts/2025_q...
unitary.foundation/posts/2025_q...
September 4, 2025 at 8:22 AM
It is that time of year again! The @unitary.foundation qOSS survey is here! Please consider filling it out if you are using, developing or maintaining any quantum OSS like @pennylaneai.bsky.social or similar
unitary.foundation/posts/2025_q...
unitary.foundation/posts/2025_q...
June 26, 2025 at 12:12 PM
June 4, 2025 at 3:46 PM
Trying to understand fault tolerant architectures without getting into the nitty gritty details of surface code physics:
The Game of Surface Codes 🐉
pennylane.ai/qml/demos/tu...
The Game of Surface Codes 🐉
pennylane.ai/qml/demos/tu...
June 3, 2025 at 1:46 PM
Trying to understand fault tolerant architectures without getting into the nitty gritty details of surface code physics:
The Game of Surface Codes 🐉
pennylane.ai/qml/demos/tu...
The Game of Surface Codes 🐉
pennylane.ai/qml/demos/tu...
firefox has this, also possibility to select multiple tabs via shift or cmd and then close with cmd+W :)
March 28, 2025 at 11:56 AM
firefox has this, also possibility to select multiple tabs via shift or cmd and then close with cmd+W :)
In particular I find it pretty weird to contribute to such a news article underlining the story that dwaves simulations are spoofed (using laptops!) and then go "well we didnt actually simualte it in full, but we could, we just dont want to" 🤷🤷🤷
March 13, 2025 at 3:25 PM
In particular I find it pretty weird to contribute to such a news article underlining the story that dwaves simulations are spoofed (using laptops!) and then go "well we didnt actually simualte it in full, but we could, we just dont want to" 🤷🤷🤷
Yet, you get headlines like these, which I find weird at best
www.newscientist.com/article/2471... In particular the part about a laptop beating dwaves experiments is pretty misleading as for TNs its just small scale experiments and in the other done using 4 GPUs (as written in the article itself)
www.newscientist.com/article/2471... In particular the part about a laptop beating dwaves experiments is pretty misleading as for TNs its just small scale experiments and in the other done using 4 GPUs (as written in the article itself)
March 13, 2025 at 3:25 PM
Yet, you get headlines like these, which I find weird at best
www.newscientist.com/article/2471... In particular the part about a laptop beating dwaves experiments is pretty misleading as for TNs its just small scale experiments and in the other done using 4 GPUs (as written in the article itself)
www.newscientist.com/article/2471... In particular the part about a laptop beating dwaves experiments is pretty misleading as for TNs its just small scale experiments and in the other done using 4 GPUs (as written in the article itself)
when you accidentally drink non-decaf coffee and your brain is yelling every thought aaaaaaaaaa
January 24, 2025 at 11:17 AM
when you accidentally drink non-decaf coffee and your brain is yelling every thought aaaaaaaaaa
Good day! You can seal the deal and delete the account altogether
January 22, 2025 at 3:18 PM
Good day! You can seal the deal and delete the account altogether
Seeing our software and resources be used by other researchers and practitioners in the qc space gives me extreme "academic pride", for a lack of better words 🥲
Here's to more well-documented code in 2025
Here's to more well-documented code in 2025
December 20, 2024 at 2:13 PM
Seeing our software and resources be used by other researchers and practitioners in the qc space gives me extreme "academic pride", for a lack of better words 🥲
Here's to more well-documented code in 2025
Here's to more well-documented code in 2025
Loved this! In particular this closing statement clicked for me :)
November 25, 2024 at 8:41 PM
Loved this! In particular this closing statement clicked for me :)
It's not perfect, but a great watch. I haven't thought that much about conservation of momentum since undergrad 🥲
October 19, 2023 at 4:56 PM
It's not perfect, but a great watch. I haven't thought that much about conservation of momentum since undergrad 🥲
We also run experiments on real quantum hardware, accessing OQC Lucy through Amazon Braket in PennyLane.
10/11
10/11
October 2, 2023 at 11:23 AM
We also run experiments on real quantum hardware, accessing OQC Lucy through Amazon Braket in PennyLane.
10/11
10/11
The advantage of ODEgen is that the resulting gradients are analytic.
Comparing VQE runs with stochastic parameter shift (SPS) gradients, starting from the same initial values, we reach lower energies with ODEgen while using fewer quantum resources.
9/11
Comparing VQE runs with stochastic parameter shift (SPS) gradients, starting from the same initial values, we reach lower energies with ODEgen while using fewer quantum resources.
9/11
October 2, 2023 at 11:22 AM
The advantage of ODEgen is that the resulting gradients are analytic.
Comparing VQE runs with stochastic parameter shift (SPS) gradients, starting from the same initial values, we reach lower energies with ODEgen while using fewer quantum resources.
9/11
Comparing VQE runs with stochastic parameter shift (SPS) gradients, starting from the same initial values, we reach lower energies with ODEgen while using fewer quantum resources.
9/11
Finally, we decompose the effective generator into Pauli words and construct simple shift rules with two terms.
8/11
8/11
October 2, 2023 at 11:22 AM
Finally, we decompose the effective generator into Pauli words and construct simple shift rules with two terms.
8/11
8/11
You may ask, what is the point to using a quantum computer in the first place here, then?
As is common practice in quantum algorithms, we consider cases where a sufficiently expressive large ansatz circuit is constructed from multiple smaller but controllable constituents.
7/11
As is common practice in quantum algorithms, we consider cases where a sufficiently expressive large ansatz circuit is constructed from multiple smaller but controllable constituents.
7/11
October 2, 2023 at 11:21 AM
You may ask, what is the point to using a quantum computer in the first place here, then?
As is common practice in quantum algorithms, we consider cases where a sufficiently expressive large ansatz circuit is constructed from multiple smaller but controllable constituents.
7/11
As is common practice in quantum algorithms, we consider cases where a sufficiently expressive large ansatz circuit is constructed from multiple smaller but controllable constituents.
7/11
We use differentiable ordinary differential equation (ODE) solvers to compute both U and its gradient ∇U in a forward/backward pass.
In this way, the complication due to the time dynamics is taken care of by classical simulation.
6/11
In this way, the complication due to the time dynamics is taken care of by classical simulation.
6/11
October 2, 2023 at 11:21 AM
We use differentiable ordinary differential equation (ODE) solvers to compute both U and its gradient ∇U in a forward/backward pass.
In this way, the complication due to the time dynamics is taken care of by classical simulation.
6/11
In this way, the complication due to the time dynamics is taken care of by classical simulation.
6/11
Instead, we look for so-called effective generators 𝓗 that encapsulate the derivative of the pulse gate U.
But how do we obtain 𝓗?
5/11
But how do we obtain 𝓗?
5/11
October 2, 2023 at 11:20 AM
Instead, we look for so-called effective generators 𝓗 that encapsulate the derivative of the pulse gate U.
But how do we obtain 𝓗?
5/11
But how do we obtain 𝓗?
5/11
One way to compute the gradients of such a pulse program is via the stochastic parameter shift rule.
However, this involves a Monte Carlo Integration, which, on the other hand, necessitates executing quantum circuits for many intermediate times τ.
4/11
However, this involves a Monte Carlo Integration, which, on the other hand, necessitates executing quantum circuits for many intermediate times τ.
4/11
October 2, 2023 at 11:20 AM
One way to compute the gradients of such a pulse program is via the stochastic parameter shift rule.
However, this involves a Monte Carlo Integration, which, on the other hand, necessitates executing quantum circuits for many intermediate times τ.
4/11
However, this involves a Monte Carlo Integration, which, on the other hand, necessitates executing quantum circuits for many intermediate times τ.
4/11