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Category: quantum physics – Page 4

Quantum Dot DBR Lasers Monolithically Integrated on Silicon Photonics by In-Pocket Heteroepitaxy

Monolithically integrated lasers on silicon photonics enable scalable, foundry-compatible production for data communications applications. However, material mismatches in heteroepitaxial systems and high coupling losses pose challenges for III-V integration on silicon. We combine three techniques: recessed silicon pockets for III-V growth, two-step heteroepitaxy using both MOCVD and MBE, and a polymer facet gap-fill approach to develop O-band InAs quantum dot lasers monolithically integrated on silicon photonics chiplets. Lasers coupled to silicon ring resonators and silicon nitride distributed Bragg reflectors (DBR) demonstrate single-mode lasing with side-mode suppression ratio up to 32 dB. Devices lase at temperatures up to 105 °C with an extrapolated operational lifetime of 6.2 years at 35 °C.

Quantum internet moves closer as researchers teleport light-based information

Quantum teleportation is a fascinating process that involves transferring a particle’s quantum state to another distant location, without moving or detecting the particle itself. This process could be central to the realization of a so-called “quantum internet,” a version of the internet that enables the safe and instant transmission of quantum information between devices within the same network.

Quantum teleportation is far from a recent idea, as it was experimentally realized several times in the past. Nonetheless, most previous demonstrations utilized frequency conversion rather than natively operating in the telecom band.

Researchers at Nanjing University recently demonstrated the teleportation of a telecom-wavelength photonic qubit (i.e., a encoded in light at the same wavelengths supporting current communications) to a telecom quantum memory. Their paper, published in Physical Review Letters, could open new possibilities for the realization of scalable quantum networks and thus potentially a quantum internet.

Wellesley team’s new research on anesthesia unlocks important clues about the nature of consciousness

For decades, one of the most fundamental and vexing questions in neuroscience has been: what is the physical basis of consciousness in the brain? Most researchers favor classical models, based on classical physics, while a minority have argued that consciousness must be quantum in nature, and that its brain basis is a collective quantum vibration of “microtubule” proteins inside neurons.

New research by Wellesley College professor Mike Wiest and a group of Wellesley College undergraduate students has yielded important experimental results relevant to this debate, by examining how anesthesia affects the brain. Wiest and his research team found that when they gave rats a drug that binds to microtubules, it took the rats significantly longer to fall unconscious under an anesthetic gas. The research team’s microtubule-binding drug interfered with the anesthetic action, thus supporting the idea that the anesthetic acts on microtubules to cause unconsciousness.

“Since we don’t know of another (i.e,. classical) way that anesthetic binding to microtubules would generally reduce brain activity and cause unconsciousness,” Wiest says, “this finding supports the quantum model of consciousness.”

Nima Arkani-Hamed, Gopal Prasad Professor, School of Natural Sciences, Institute for Advanced Study

Beyond Space-Time and Quantum Mechanics.

Nima Arkani-Hamed.

(June 28, 2025)

A tribute to jim simons in celebration of the importance of basic science and mathematics.

Leaders in mathematics, science and philanthropy gathered on June 27, 2025, to remember the incredible contributions of Jim Simons and to inspire continued philanthropic support of basic research.

Continue reading “Nima Arkani-Hamed, Gopal Prasad Professor, School of Natural Sciences, Institute for Advanced Study” | >

Levin Λ Friston Λ Fields: “Meta” Hard Problem of Consciousness

Karl Friston, Michael Levin, and Chris Field sit down for an epochal conversation on cognition and consciousness.
Sponsor: Brilliant: https://brilliant.org/TOE for 20% off.

Patreon: https://patreon.com/curtjaimungal.
Crypto: https://tinyurl.com/cryptoTOE
PayPal: https://tinyurl.com/paypalTOE
Twitter: https://twitter.com/TOEwithCurt.
Discord Invite: https://discord.com/invite/kBcnfNVwqs.
iTunes: https://podcasts.apple.com/ca/podcast/better-left-unsaid-wit…1521758802
Pandora: https://pdora.co/33b9lfP
Spotify: https://open.spotify.com/show/4gL14b92xAErofYQA7bU4e.
Subreddit r/TheoriesOfEverything: https://reddit.com/r/theoriesofeverything.
Merch: https://tinyurl.com/TOEmerch.

CORRECTION:
- Chris Fields emailed me the following: “I referred to Peter Strawson when I meant to refer to his son, Galen Strawson, who has done the work on panpsychism.”

LINKS MENTIONED:
- Curt’s AMA #:3 https://youtu.be/SX9q2D6b5bc.
- Karl Friston #2: https://youtu.be/SWtFU1Lit3M
- Karl Friston #1: https://youtu.be/2v7LBABwZKA
- Michael Levin: https://youtu.be/Z0TNfysTazc.

TIMESTAMPS:
00:00:00 Introduction.
00:03:20 Michael Levin answers: “What do you respect about Chris / Karl?“
00:04:45 Chris Fields answers: “What do you respect about Michael / Karl?“
00:05:45 Karl Friston answers: “What do you respect about Chris / Michael?“
00:07:46 Self organization / Autopoiesis / Why does life form?
00:12:11 How does cognition emerge from smaller parts?
00:14:18 Why do we see “things” independent from one another? Why in space / time?
00:18:40 Relationship between cognition and consciousness.
00:22:03 The Meta Hard Problem.
00:30:37 Why is complexity associated with “awareness”?
00:35:56 Is society one large brain, with each person acting as a neuron?
00:44:17 Duality between: Did you act on the world? Or did the world act on you?
00:51:32 Babbling, and becoming a “self“
01:11:22 “300 milliseconds” is a special unit of time for consciousness.
01:15:49 Quantum Babbling.
01:21:49 The difference between “randomness” and “quantum randomness“
01:30:03 The difference between “external” and “internal” are both real and illusory.
01:33:41 Studying consciousness / the self and the concomitant existential dread.
01:48:19 Michael Levin: “Something important goes all the way down“
01:51:12 Science starts with faith.

Sensing with 2D Materials

After the successful separation of a monolayer of carbon atoms with honeycomb lattice known as graphene in 2004, a large group of 2D materials known as TMDCs and MXenes were discovered and studied. The realm of 2D materials and their heterostructures has created new opportunities for the development of various types of advanced rigid, flexible and stretchable biosensors, and chemical, optoelectronic and electrical sensors due to their unique and versatile electrical, chemical, mechanical and optical properties. The high surface to volume ratio and quantum confinement in 2D materials make them strong candidates for the development of sensors with improved sensitivity and performance. This group of atomically thin material also offer mechanical flexibility and limited stretchability harvested towards making flexible and stretchable sensors that can be used at the interface with soft tissues and in soft robotics. However, challenges remain in fully realizing their potential in practical applications.

The aim of this collection is to highlight the current progress in the research of 2D materials, focusing on their integration into sensing technologies. We seek to provide a comprehensive overview of the advancements made in this area while addressing the challenges faced in developing practical applications.

Quantum Teleportation Was Achieved Over Internet For The First Time

In 2024, a quantum state of light was successfully teleported through more than 30 kilometers (around 18 miles) of fiber optic cable amid a torrent of internet traffic – a feat of engineering once considered impossible.

The impressive demonstration by researchers in the US may not help you beam to work to beat the morning traffic, or download your favourite cat videos faster.

However, the ability to teleport quantum states through existing infrastructure represents a monumental step towards achieving a quantum-connected computing network, enhanced encryption, or powerful new methods of sensing.

Engineers achieve efficient integration of quantum dot lasers on silicon chiplets

Lasers that are fabricated directly onto silicon photonic chips offer several advantages over external laser sources, such as greater scalability. Furthermore, photonic chips with these “monolithically” integrated lasers can be commercially viable if they can be manufactured in standard semiconductor foundries.

III-V semiconductor lasers can be monolithically integrated with photonic chips by directly growing a crystalline layer of material, such as indium arsenide, on silicon substrate. However, photonic chips with such integrated laser source are challenging to manufacture due to mismatch between structures or properties of III-V semiconductor material and silicon. “Coupling loss” or the loss of optical power during transfer from laser source to silicon waveguides in the photonic chip is yet another concern when manufacturing with monolithically integrated lasers.

In a study that was recently published in the Journal of Lightwave Technology, Dr. Rosalyn Koscica from the University of California, United States, and her team successfully integrated quantum dot (QD) lasers monolithically on silicon photonics chiplets.