Thomas Colas
@cosmocolas.bsky.social
Postdoc in #cosmology at DAMTP @Cambridge_Uni | #earlyuniverse and #openEFTs 🌌
More lecture notes from the Disordered Universe Summer School are on the way! Topics include:
🌌 Λ > 0 universes (D. Anninos)
📊 Out-of-equilibrium systems (T. Anous)
🔍 Amplitudes & correlators (A. McLeod)
Stay tuned! Details: indico.sns.it/event/91/ove...
🌌 Λ > 0 universes (D. Anninos)
📊 Out-of-equilibrium systems (T. Anous)
🔍 Amplitudes & correlators (A. McLeod)
Stay tuned! Details: indico.sns.it/event/91/ove...
Summer School on The Disordered Universe
The school aims to attract graduate students as well as young postdocs interested in the areas of de Sitter physics, theoretical cosmology, holography, scattering amplitudes, open systems, and disorde...
indico.sns.it
October 2, 2025 at 1:29 PM
More lecture notes from the Disordered Universe Summer School are on the way! Topics include:
🌌 Λ > 0 universes (D. Anninos)
📊 Out-of-equilibrium systems (T. Anous)
🔍 Amplitudes & correlators (A. McLeod)
Stay tuned! Details: indico.sns.it/event/91/ove...
🌌 Λ > 0 universes (D. Anninos)
📊 Out-of-equilibrium systems (T. Anous)
🔍 Amplitudes & correlators (A. McLeod)
Stay tuned! Details: indico.sns.it/event/91/ove...
It’s been a real pleasure collaborating with physicists outside cosmology on this project. Huge thanks to Alessio, Ana, and Michał for the countless hours of discussions and the effort to bridge quantum information and cosmology 🌌⚛️[20/20]
July 17, 2025 at 9:02 AM
It’s been a real pleasure collaborating with physicists outside cosmology on this project. Huge thanks to Alessio, Ana, and Michał for the countless hours of discussions and the effort to bridge quantum information and cosmology 🌌⚛️[20/20]
...we’re effectively stuck probing a classical probability distribution — one that hides clear quantum signatures [19/20]
July 17, 2025 at 9:02 AM
...we’re effectively stuck probing a classical probability distribution — one that hides clear quantum signatures [19/20]
Even though the quantum states of cosmological inhomogeneities may show strong non-classical traits, our limited observational access during inflation means... [18/20]
July 17, 2025 at 9:02 AM
Even though the quantum states of cosmological inhomogeneities may show strong non-classical traits, our limited observational access during inflation means... [18/20]
This tension highlights a key puzzle about quantum perturbations in the early universe [17/20]
July 17, 2025 at 9:02 AM
This tension highlights a key puzzle about quantum perturbations in the early universe [17/20]
It would require accessing the decaying mode of inflationary perturbations — something that’s extremely challenging and may still fall short of true optimality [16/20]
July 17, 2025 at 9:02 AM
It would require accessing the decaying mode of inflationary perturbations — something that’s extremely challenging and may still fall short of true optimality [16/20]
But — and it’s a big but — this measurement is far beyond the reach of current observations [15/20]
July 17, 2025 at 9:02 AM
But — and it’s a big but — this measurement is far beyond the reach of current observations [15/20]
The conclusions are twofold: first, there is an optimal measurement strategy that can constrain the tensor-to-scalar ratio extremely well [14/20]
July 17, 2025 at 9:02 AM
The conclusions are twofold: first, there is an optimal measurement strategy that can constrain the tensor-to-scalar ratio extremely well [14/20]
Our main result: there is a huge gap between the classical and quantum Fisher information — one that grows exponentially with the duration of inflation [13/20]
July 17, 2025 at 9:02 AM
Our main result: there is a huge gap between the classical and quantum Fisher information — one that grows exponentially with the duration of inflation [13/20]
For concreteness, we focus on the tensor-to-scalar ratio — a key observational target in upcoming experiments [12/20]
July 17, 2025 at 9:02 AM
For concreteness, we focus on the tensor-to-scalar ratio — a key observational target in upcoming experiments [12/20]
To understand how much information we lose due to limited access to early-universe data, we contrast the quantum Fisher information — the best-case scenario — with the classical Fisher information extracted from measurements of the Gaussian curvature perturbations alone [11/20]
July 17, 2025 at 9:02 AM
To understand how much information we lose due to limited access to early-universe data, we contrast the quantum Fisher information — the best-case scenario — with the classical Fisher information extracted from measurements of the Gaussian curvature perturbations alone [11/20]
This limited observational access makes it much harder to reconstruct the quantum state produced by inflation [10/20]
July 17, 2025 at 9:02 AM
This limited observational access makes it much harder to reconstruct the quantum state produced by inflation [10/20]
Key features — like non-Gaussianities in scalar perturbations, primordial gravitational wave statistics, or momentum correlations — are either weakly constrained or not measured at all [9/20]
July 17, 2025 at 9:02 AM
Key features — like non-Gaussianities in scalar perturbations, primordial gravitational wave statistics, or momentum correlations — are either weakly constrained or not measured at all [9/20]
Unfortunately, our window into the early Universe is still pretty narrow [8/20]
July 17, 2025 at 9:02 AM
Unfortunately, our window into the early Universe is still pretty narrow [8/20]
It sets the ultimate limit on how precisely we could measure a parameter — if we had ideal access to the early Universe’s quantum state [7/20]
July 17, 2025 at 9:02 AM
It sets the ultimate limit on how precisely we could measure a parameter — if we had ideal access to the early Universe’s quantum state [7/20]
So how do we approach this? We bring in quantum metrology — specifically, the quantum Fisher information — and apply it to the state of cosmological fluctuations right after inflation [6/20]
July 17, 2025 at 9:02 AM
So how do we approach this? We bring in quantum metrology — specifically, the quantum Fisher information — and apply it to the state of cosmological fluctuations right after inflation [6/20]
This raises two deep questions:
· How well can we infer a given parameter?
· What’s the best way to do it? [5/20]
· How well can we infer a given parameter?
· What’s the best way to do it? [5/20]
July 17, 2025 at 9:02 AM
This raises two deep questions:
· How well can we infer a given parameter?
· What’s the best way to do it? [5/20]
· How well can we infer a given parameter?
· What’s the best way to do it? [5/20]
I've always found it wild that we just collect photons with telescopes — and somehow extract things like the dark matter abundance or the Universe’s expansion rate [4/20]
July 17, 2025 at 9:02 AM
I've always found it wild that we just collect photons with telescopes — and somehow extract things like the dark matter abundance or the Universe’s expansion rate [4/20]
In cosmology, this process shapes nearly everything we know about the Universe: its composition, its history, its fate [3/20]
July 17, 2025 at 9:02 AM
In cosmology, this process shapes nearly everything we know about the Universe: its composition, its history, its fate [3/20]
Estimating the values of a model’s parameters — what we call parameter inference — lies at the heart of scientific discovery [2/20]
July 17, 2025 at 9:02 AM
Estimating the values of a model’s parameters — what we call parameter inference — lies at the heart of scientific discovery [2/20]
After more than a year of questions, setbacks, and slow progress, this work finally took shape. Huge thanks to the physicists who joined the journey, especially my past and present collaborators [25/25]
July 8, 2025 at 9:07 AM
After more than a year of questions, setbacks, and slow progress, this work finally took shape. Huge thanks to the physicists who joined the journey, especially my past and present collaborators [25/25]
We recomputed the primordial tensor spectrum for this model and derived the tensor-to-scalar ratio. Using BICEP’s current bound, r < 0.036, we placed an upper limit on noise sourcing tensors during inflation [24/25]
July 8, 2025 at 9:07 AM
We recomputed the primordial tensor spectrum for this model and derived the tensor-to-scalar ratio. Using BICEP’s current bound, r < 0.036, we placed an upper limit on noise sourcing tensors during inflation [24/25]
Interestingly, dissipative birefringence appears at lower derivative order than conservative birefringence. Exploring explicit models that realize this would be an exciting direction [23/25]
July 8, 2025 at 9:07 AM
Interestingly, dissipative birefringence appears at lower derivative order than conservative birefringence. Exploring explicit models that realize this would be an exciting direction [23/25]