# Latest
**URL:** https://discuss.pennylane.ai/latest.md?page=1
[Latest](https://discuss.pennylane.ai/latest.md) · [Categories](https://discuss.pennylane.ai/categories.md)
**Page:** 2
---
## [MrMustard for GKP state preparation](https://discuss.pennylane.ai/t/mrmustard-for-gkp-state-preparation/9401)
**Author:** [@Amanuel](https://discuss.pennylane.ai/u/Amanuel)\
**Replies:** 4\
**Last updated:** [July 14, 2026, 12:44am UTC](https://discuss.pennylane.ai/t/mrmustard-for-gkp-state-preparation/9401 "2026-07-14T00:44:56Z")
Hello are there tutorials available for performing non-Gaussian state preparation with a GBS device using the latest version of the MrMustard library? I am trying to investigate the capabilities of MrMustard for heraldin…
---
## [How can I natively parallelize my batch calculations and leverage the GPU with an accelerated simulator backend](https://discuss.pennylane.ai/t/how-can-i-natively-parallelize-my-batch-calculations-and-leverage-the-gpu-with-an-accelerated-simulator-backend/9407)
**Author:** [@Jay\_Prakash](https://discuss.pennylane.ai/u/Jay_Prakash)\
**Replies:** 4\
**Last updated:** [July 14, 2026, 12:39am UTC](https://discuss.pennylane.ai/t/how-can-i-natively-parallelize-my-batch-calculations-and-leverage-the-gpu-with-an-accelerated-simulator-backend/9407 "2026-07-14T00:39:24Z")
Performance Bottleneck: When running this loop on a CUDA-enabled session, active GPU utilization scales down completely to 0.00% while a single thread on the CPU spikes to 100%. If I remove the explicit \`.cpu()\` cast fro…
---
## [Normalization in qp.BlockEncode](https://discuss.pennylane.ai/t/normalization-in-qp-blockencode/9397)
**Author:** [@ttaka](https://discuss.pennylane.ai/u/ttaka)\
**Replies:** 3\
**Last updated:** [July 10, 2026, 1:52am UTC](https://discuss.pennylane.ai/t/normalization-in-qp-blockencode/9397 "2026-07-10T01:52:02Z")
Hi, I am a newbie for Pennylane as well as quantum computing itself. I am trying to understand the QSVT and apply my dense and asymmetric matrices. Since the norm of such a matrix (say A) is usually grater than one, qp.…
---
## [Quantum key distribution](https://discuss.pennylane.ai/t/quantum-key-distribution/9399)
**Author:** [@krish\_18](https://discuss.pennylane.ai/u/krish_18)\
**Replies:** 1\
**Last updated:** [July 10, 2026, 1:33am UTC](https://discuss.pennylane.ai/t/quantum-key-distribution/9399 "2026-07-10T01:33:44Z")
i want to know fullly and detailed abuut quantum key distribution including practical ways implementation with pennylane
---
## [HS.5.2 polynomial](https://discuss.pennylane.ai/t/hs-5-2-polynomial/9393)
**Author:** [@mchau](https://discuss.pennylane.ai/u/mchau)\
**Replies:** 2\
**Last updated:** [July 7, 2026, 4:20pm UTC](https://discuss.pennylane.ai/t/hs-5-2-polynomial/9393 "2026-07-07T16:20:55Z")
The exercise is from the link above. We need to use QSP to estimate the \\text{erf} function. I tried to solve that without viewing the hint by estimating the Chebyshev series of erf. I run this externally and copy the …
---
## [PennyLane Challenge: Revisiting Schrodinger's cat](https://discuss.pennylane.ai/t/pennylane-challenge-revisiting-schrodingers-cat/4509)
**Author:** [@CatalinaAlbornoz](https://discuss.pennylane.ai/u/CatalinaAlbornoz)\
**Replies:** 5\
**Last updated:** [July 3, 2026, 1:30am UTC](https://discuss.pennylane.ai/t/pennylane-challenge-revisiting-schrodingers-cat/4509 "2026-07-03T01:30:26Z")
Use this topic to ask your questions about the PennyLane Challenge: Revisiting Schrodinger’s cat.
---
## [Numpy version incompatibility with Pennylane](https://discuss.pennylane.ai/t/numpy-version-incompatibility-with-pennylane/9383)
**Author:** [@mlowe](https://discuss.pennylane.ai/u/mlowe)\
**Replies:** 8\
**Last updated:** [June 25, 2026, 3:59pm UTC](https://discuss.pennylane.ai/t/numpy-version-incompatibility-with-pennylane/9383 "2026-06-25T15:59:36Z")
I am running the latest version of Pennylane 0.45.0 in a Jupyter notebook. However I am receiving Numpy errors (particularly regarding msort and linalg) when I run “import pennylane as qml”. This occurs when using numpy …
---
## [Stuck on HS.1.4](https://discuss.pennylane.ai/t/stuck-on-hs-1-4/9389)
**Author:** [@lemjm](https://discuss.pennylane.ai/u/lemjm)\
**Replies:** 1\
**Last updated:** [June 23, 2026, 10:28pm UTC](https://discuss.pennylane.ai/t/stuck-on-hs-1-4/9389 "2026-06-23T22:28:25Z")
Hi. I’m currently stuck on codercise HS.1.4. I think I understand the theory, but somehow can manage to get my code accepted. Can anyone help me ? Here are my attempts :
---
## ["typo" in codercise V1.1](https://discuss.pennylane.ai/t/typo-in-codercise-v1-1/9279)
**Author:** [@kasterma](https://discuss.pennylane.ai/u/kasterma)\
**Replies:** 2\
**Last updated:** [June 23, 2026, 8:29pm UTC](https://discuss.pennylane.ai/t/typo-in-codercise-v1-1/9279 "2026-06-23T20:29:09Z")
def basic\_entangling\_ansatz(observable,params): “”"Applies an ansatz with basic entanglement. Args: observable (qml.op): a pennylane operator whose expectation value we want to measure. params(np.ar…
---
## [QAOA Workflow: contradictory information](https://discuss.pennylane.ai/t/qaoa-workflow-contradictory-information/9350)
**Author:** [@fyellin](https://discuss.pennylane.ai/u/fyellin)\
**Replies:** 4\
**Last updated:** [June 22, 2026, 10:07pm UTC](https://discuss.pennylane.ai/t/qaoa-workflow-contradictory-information/9350 "2026-06-22T22:07:54Z")
I’m confused by two seemingly contradictory steps in the QAOA workflow. Define the mixer Hamiltonion. . . A common choice for H\_m is … \\sum{X\_j} Initialize the quantum system in the ground state of H\_m which is usuall…
---
## [Differentiable Gaussian Backend for CV Quantum ML](https://discuss.pennylane.ai/t/differentiable-gaussian-backend-for-cv-quantum-ml/9379)
**Author:** [@Louis\_Choron](https://discuss.pennylane.ai/u/Louis_Choron)\
**Replies:** 2\
**Last updated:** [June 11, 2026, 6:09pm UTC](https://discuss.pennylane.ai/t/differentiable-gaussian-backend-for-cv-quantum-ml/9379 "2026-06-11T18:09:08Z")
I am conducting research in continuous-variable (CV) quantum machine learning (ML) and have identified some strong limitations in PennyLane’s Gaussian backend that hinder its use in this area of research. I would like to…
---
## [QSVT with non-symmetric phase factors (real polynomial- no LCU)](https://discuss.pennylane.ai/t/qsvt-with-non-symmetric-phase-factors-real-polynomial-no-lcu/9356)
**Author:** [@Joel](https://discuss.pennylane.ai/u/Joel)\
**Replies:** 4\
**Last updated:** [June 1, 2026, 10:28pm UTC](https://discuss.pennylane.ai/t/qsvt-with-non-symmetric-phase-factors-real-polynomial-no-lcu/9356 "2026-06-01T22:28:14Z")
Hi, I have been following the two demos on implementing QSVT in Pennylane: QSVT in practice and How to implement QSVT on hardware using angles calculated using the \`laurent\` method in PyQSP. As I understand it (and as I …
---
## [Linear System Question](https://discuss.pennylane.ai/t/linear-system-question/9349)
**Author:** [@movingwaters](https://discuss.pennylane.ai/u/movingwaters)\
**Replies:** 2\
**Last updated:** [May 28, 2026, 2:05pm UTC](https://discuss.pennylane.ai/t/linear-system-question/9349 "2026-05-28T14:05:25Z")
Hello, I’ve seen topics regarding solving systems of linear equations and formulas for Ax=b with quantum algorithms that are solving for the x if we have A and b. I’m wondering if we are just wanting to apply x on a mat…
---
## [The new PennyLane Codebook is here!](https://discuss.pennylane.ai/t/the-new-pennylane-codebook-is-here/4595)
**Author:** [@discourse-admin](https://discuss.pennylane.ai/u/discourse-admin)\
**Replies:** 2\
**Last updated:** [May 27, 2026, 12:23am UTC](https://discuss.pennylane.ai/t/the-new-pennylane-codebook-is-here/4595 "2026-05-27T00:23:33Z")
Meet the new Codebook! Learn quantum computing with PennyLane — the leading tool for programming quantum computers. Share your feedback about the new Codebook here!
---
## [PennyLane x unitaryHACK2026 challenge](https://discuss.pennylane.ai/t/pennylane-x-unitaryhack2026-challenge/9345)
**Author:** [@CatalinaAlbornoz](https://discuss.pennylane.ai/u/CatalinaAlbornoz)\
**Replies:** 0\
**Last updated:** [May 26, 2026, 4:01am UTC](https://discuss.pennylane.ai/t/pennylane-x-unitaryhack2026-challenge/9345 "2026-05-26T04:01:00Z")
Use this topic to ask your questions about the PennyLane x unitaryHACK2026 challenge. You can earn an exclusive, time-limited badge for completing it!
---
## [What does "Error '00' mean?](https://discuss.pennylane.ai/t/what-does-error-00-mean/9347)
**Author:** [@fyellin](https://discuss.pennylane.ai/u/fyellin)\
**Replies:** 5\
**Last updated:** [May 25, 2026, 5:51pm UTC](https://discuss.pennylane.ai/t/what-does-error-00-mean/9347 "2026-05-25T17:51:54Z")
I’m running PF.5.1. My code runs. I get the printed output: the success probability is 0.2524 which is roughly what I expected but then above that I see a red stripe above my user output with the message Error '00'. …
---
## [Codebook: Variational Quantum Eigensolver](https://discuss.pennylane.ai/t/codebook-variational-quantum-eigensolver/7224)
**Author:** [@CatalinaAlbornoz](https://discuss.pennylane.ai/u/CatalinaAlbornoz)\
**Replies:** 9\
**Last updated:** [May 19, 2026, 4:34pm UTC](https://discuss.pennylane.ai/t/codebook-variational-quantum-eigensolver/7224 "2026-05-19T16:34:43Z")
Ask here about the “Variational Quantum Eigensolver” Codebook topic from the “Introduction to Variational Quantum Algorithms” module.
---
## [Codercise G.5.1 - Preparing a multi-solution oracle](https://discuss.pennylane.ai/t/codercise-g-5-1-preparing-a-multi-solution-oracle/9335)
**Author:** [@delacroissant](https://discuss.pennylane.ai/u/delacroissant)\
**Replies:** 1\
**Last updated:** [May 13, 2026, 4:10pm UTC](https://discuss.pennylane.ai/t/codercise-g-5-1-preparing-a-multi-solution-oracle/9335 "2026-05-13T16:10:11Z")
In Codercise G.5.1 it is written: Let’s start by coding up this new oracle. Create an oracle for a random solution set of a given size using the MultiControlledX gate. Remember that this takes a string for control\_value…
---
## [Small typo in Codercise F.1.3 - The nearest power of 2](https://discuss.pennylane.ai/t/small-typo-in-codercise-f-1-3-the-nearest-power-of-2/9336)
**Author:** [@delacroissant](https://discuss.pennylane.ai/u/delacroissant)\
**Replies:** 2\
**Last updated:** [May 13, 2026, 7:23am UTC](https://discuss.pennylane.ai/t/small-typo-in-codercise-f-1-3-the-nearest-power-of-2/9336 "2026-05-13T07:23:37Z")
There is a small typo in the firsy hint in Codercise F.1.3. The text says: Let’s look at simple example, we want to find the nearest power of 2 of x = 16 (which is 16, of course). but instead it should say: “which i…
---
## [PennyLane v0.45 Challenge: Resource Estimation](https://discuss.pennylane.ai/t/pennylane-v0-45-challenge-resource-estimation/9337)
**Author:** [@dren](https://discuss.pennylane.ai/u/dren)\
**Replies:** 0\
**Last updated:** [May 12, 2026, 4:40pm UTC](https://discuss.pennylane.ai/t/pennylane-v0-45-challenge-resource-estimation/9337 "2026-05-12T16:40:55Z")
Use this topic to ask your questions about the PennyLane Challenge: Introduction to Resource Estimation. You can earn a badge for completing it!
---
## [Regarding the lecture of pennylane](https://discuss.pennylane.ai/t/regarding-the-lecture-of-pennylane/9321)
**Author:** [@ajcodes](https://discuss.pennylane.ai/u/ajcodes)\
**Replies:** 3\
**Last updated:** [May 8, 2026, 1:32am UTC](https://discuss.pennylane.ai/t/regarding-the-lecture-of-pennylane/9321 "2026-05-08T01:32:19Z")
Hi @CatalinaAlbornoz, I’ve been following your lectures on PennyLane via the Wiser platform and found them incredibly insightful. The way you bridge the gap between quantum theory and differentiable programming is amazi…
---
## [Training QSP Phase Angles Directly with Gradient Descent](https://discuss.pennylane.ai/t/training-qsp-phase-angles-directly-with-gradient-descent/9320)
**Author:** [@rosspeili](https://discuss.pennylane.ai/u/rosspeili)\
**Replies:** 1\
**Last updated:** [April 30, 2026, 6:31pm UTC](https://discuss.pennylane.ai/t/training-qsp-phase-angles-directly-with-gradient-descent/9320 "2026-04-30T18:31:07Z")
Quantum Signal Processing (QSP) is one of those beautiful algorithms that promises to turn a few qubits and some carefully chosen rotation angles into useful polynomial transformations. It’s a foundational block for Hami…
---
## [Availability of qrackbind for PennyLane](https://discuss.pennylane.ai/t/availability-of-qrackbind-for-pennylane/9319)
**Author:** [@stokomax](https://discuss.pennylane.ai/u/stokomax)\
**Replies:** 1\
**Last updated:** [April 29, 2026, 9:17pm UTC](https://discuss.pennylane.ai/t/availability-of-qrackbind-for-pennylane/9319 "2026-04-29T21:17:04Z")
Hello! I am seeking feedback and a few brave souls to test a new Qrack python binding package called qrackbind. The package includes a few PennyLane devices which are discussed in the README. As noted in the project REA…
---
## [An issue in the FALQON demo](https://discuss.pennylane.ai/t/an-issue-in-the-falqon-demo/9290)
**Author:** [@adityab](https://discuss.pennylane.ai/u/adityab)\
**Replies:** 5\
**Last updated:** [April 27, 2026, 9:55pm UTC](https://discuss.pennylane.ai/t/an-issue-in-the-falqon-demo/9290 "2026-04-27T21:55:55Z")
Hi all, I am a new user of Pennylane and the awesome set of demos have been really helpful to get me started. This post is about the demo on feedback-assisted quantum optimization (FALQON). There seem to be a couple of…
---
## [Access to Xanadu's Quantum hardware](https://discuss.pennylane.ai/t/access-to-xanadus-quantum-hardware/9317)
**Author:** [@gopalsahu](https://discuss.pennylane.ai/u/gopalsahu)\
**Replies:** 1\
**Last updated:** [April 22, 2026, 6:46pm UTC](https://discuss.pennylane.ai/t/access-to-xanadus-quantum-hardware/9317 "2026-04-22T18:46:54Z")
How can we access Xanadu’s Quantum hardware for academic research ?
---
## [Non-monotonic realization error in hamiltonian simulation of qubitized operator with GQSP](https://discuss.pennylane.ai/t/non-monotonic-realization-error-in-hamiltonian-simulation-of-qubitized-operator-with-gqsp/9303)
**Author:** [@incud](https://discuss.pennylane.ai/u/incud)\
**Replies:** 3\
**Last updated:** [April 16, 2026, 3:35pm UTC](https://discuss.pennylane.ai/t/non-monotonic-realization-error-in-hamiltonian-simulation-of-qubitized-operator-with-gqsp/9303 "2026-04-16T15:35:31Z")
Hello! I’m using the recent GQSP functionality to implement Hamiltonian simulation of a qubitized operator (cf. Corollary 8 of https://arxiv.org/pdf/2308.01501). To the best of my understanding, the reference constructi…
---
## [Third-party PennyLane plugin for exact and MPS lattice workflows](https://discuss.pennylane.ai/t/third-party-pennylane-plugin-for-exact-and-mps-lattice-workflows/9304)
**Author:** [@gwen](https://discuss.pennylane.ai/u/gwen)\
**Replies:** 1\
**Last updated:** [April 15, 2026, 11:08pm UTC](https://discuss.pennylane.ai/t/third-party-pennylane-plugin-for-exact-and-mps-lattice-workflows/9304 "2026-04-15T23:08:46Z")
I would like to share a third-party PennyLane plugin package that is now working through the standard plugin discovery path, and ask whether there is a recommended process for listing or announcing third-party PennyLane …
---
## [Lightning.qubit with reuploading model](https://discuss.pennylane.ai/t/lightning-qubit-with-reuploading-model/9300)
**Author:** [@Jacob\_Cybulski](https://discuss.pennylane.ai/u/Jacob_Cybulski)\
**Replies:** 4\
**Last updated:** [April 13, 2026, 11:24pm UTC](https://discuss.pennylane.ai/t/lightning-qubit-with-reuploading-model/9300 "2026-04-13T23:24:41Z")
I have a simple reuploading test model, i.e. @qml.qnode(dev, diff\_method='adjoint') # 'adjoint' or 'parameter-shift' def qnn\_model(params, x): for l in range(n\_layers): for q in range(n\_qubits): …
---
## [PF4.4 Differentiate and repear](https://discuss.pennylane.ai/t/pf4-4-differentiate-and-repear/9293)
**Author:** [@simpsoe](https://discuss.pennylane.ai/u/simpsoe)\
**Replies:** 1\
**Last updated:** [March 30, 2026, 8:29pm UTC](https://discuss.pennylane.ai/t/pf4-4-differentiate-and-repear/9293 "2026-03-30T20:29:08Z")
Having trouble with this and got stuck. Any help is appreciated. dev = qml.device("default.qubit", wires = 2) @qml.qnode(dev, diff\_method = "parameter-shift", max\_diff = 2) def circuit\_for\_hessian(params): """ Implemen…
---
## [Overusing Catalyst callbacks](https://discuss.pennylane.ai/t/overusing-catalyst-callbacks/9284)
**Author:** [@sergeimironov](https://discuss.pennylane.ai/u/sergeimironov)\
**Replies:** 2\
**Last updated:** [March 20, 2026, 10:24am UTC](https://discuss.pennylane.ai/t/overusing-catalyst-callbacks/9284 "2026-03-20T10:24:38Z")
Hihi! I’m exploring an application for Catalyst callbacks where I need to call a Python function that doesn’t particularly fit into the ‘pure\_callback’ requirement from the docs. Concretely, my function accesses a global…
[Previous page](https://discuss.pennylane.ai/latest.md)
[Next page](https://discuss.pennylane.ai/latest.md?page=2)