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Mattia Walschaers

@walschaers.eu

CNRS researcher @lkblab.bsky.social in Paris. Theoretical quantum physicist, working on quantum optics, and continuous-variable systems. (Pour-over) coffee nerd ☕️ He/him

154 Posts840 Follower1249 Folgt
Mattia Walschaers@walschaers.eu · last yr.

Not sure if there are any #coffee lovers out there among my followers? If so, this one's for you. ☕ I just got a Hario Switch after a lot of hesitation, thinking that it would not make much of a difference. After brewing a few cups with it, I am genuinely amazed by the result. Strongly recommended!

Mattia Walschaers@walschaers.eu · last yr.

What happens when you put a bunch of highly talented first-year master students together with a brilliant post-doc? First, there is a lot of magic involving algebraic geometry and then you have a protocol for generating arbitrary multimode multi-photon states! 💪 arxiv.org/abs/2507.19397

An image of a photonic circuit. Starting from vacuum states, photon creation operators and interferometers (denoted U) are applied in an alternating fashion. At the end, the top mode is measured with a photon-number resolving detector, and upon the second mode one applies a displacement operator and then postselects on a zero-photon count. The remaining modes are indicated to be in a state denoted as psi.
Emmanuel Flurin@manuflurin.bsky.social · last yr.

New paper out! We resonantly couple a superconducting heavy-fluxonium qubit ⚛️ to a macroscopic membrane 🥁 oscillating at a few MHz. ~300 repeated interactions let us track its quantum motion, observe back-action & probe non-commuting operators. Diósi–Penrose next? (1/8) arxiv.org/abs/2505.21481

Probing the quantum motion of a macroscopic mechanical oscillator with a radio-frequency superconducting qubit

Long-lived mechanical resonators like drums oscillating at MHz frequencies and operating in the quantum regime offer a powerful platform for quantum technologies and tests of fundamental physics. Yet,...

arxiv.org

Mattia Walschaers@walschaers.eu · last yr.

Our paper "Purification of Gaussian states by photon subtraction or addition" is now published in PRA! 🎉 We explore how, surprisingly, photon subtraction and addition can enhance Gaussian state purity, revealing new potential in quantum optics. journals.aps.org/pra/abstract... #QuantumOptics

Purification of Gaussian states by photon subtraction or addition

Photon subtraction (PS) can enhance entanglement, which, for pure states, induces a decrease in the purity of reduced states. In contrast, by analyzing the purities of Gaussian states before and after...

journals.aps.org

Mattia Walschaers@walschaers.eu · last yr.

🌟 Quantum Community, Help Needed! 🌟 My tutorial "Non-Gaussian States and Where to Find Them" needs a few updates. If you've spotted errors, please share! Let's improve it together. journals.aps.org/prxquantum/a... #QuantumOptics #Feedback

Non-Gaussian Quantum States and Where to Find Them

A phase-space exploration of continuous-variable systems is presented, guiding newcomers through the methodology needed for investigating non-Gaussian states.

journals.aps.org

Mattia Walschaers@walschaers.eu · 2y ago

Now that I have some time. Here are a few more words on this work. At its root, this work started from a simple question: is non-Gaussianity fundamentally useful in quantum metrology?

Mattia Walschaers@walschaers.eu · 2y ago

📃 Heisenberg put limits on how well we can jointly *measure* position and momentum. However, these limits do not apply in the framework of estimation theory. In our new work, we show that non-Gaussianity is a crucial resource to increase precision in such estimation. arxiv.org/abs/2504.01910

Mattia Walschaers@walschaers.eu · 2y ago

📃 Heisenberg put limits on how well we can jointly *measure* position and momentum. However, these limits do not apply in the framework of estimation theory. In our new work, we show that non-Gaussianity is a crucial resource to increase precision in such estimation. arxiv.org/abs/2504.01910

Joint estimation of position and momentum with arbitrarily high precision using non-Gaussian states

We address the joint estimation of changes in the position and linear momentum of a quantum particle or, equivalently, changes in the complex field of a bosonic mode. Although these changes are genera...

arxiv.org

Mattia Walschaers@walschaers.eu · 2y ago

What saddens me about public debate France today is that there seems to be more outrage about someone being excluded from an election rather than about that someone stealing over 4 million euros of our money...

Mattia Walschaers@walschaers.eu · 2y ago

Want to be sure not to add the wrong person to your group chat? Perhaps quantum communication might be a thing for you! Here we investigate under which conditions providers can safely establish entanglement links between two end-users : arxiv.org/abs/2503.20547

Entanglement routing via passive optics in CV-networks

Large-scale operations in quantum networks require efficient sorting of desired paths between nodes. In this article, we consider entanglement routing, which involves establishing an entanglement link...

arxiv.org