Lifeboat Foundation

The dream of building a practical, fault-tolerant quantum computer has taken a significant step forward.

In a breakthrough study recently published in Nature, researchers from Google DeepMind and Google Quantum AI said they have developed an AI-based decoder, AlphaQubit, which drastically improves the accuracy of quantum error correction—a critical challenge in quantum computing.

“Our work illustrates the ability of machine learning to go beyond human-designed algorithms by learning from data directly, highlighting machine learning as a strong contender for decoding in quantum computers,” researchers wrote.

Nonlinear optics explores how powerful light (e.g. lasers) interacts with materials, resulting in the output light changing colour (i.e. frequency) or behaving differently based on the intensity of the incoming light. This field is crucial for developing advanced technologies such as high-speed communication systems and laser-based applications. Nonlinear optical phenomena enable the manipulation of light in novel ways, leading to breakthroughs in fields like telecommunications, medical imaging, and quantum computing. Two-dimensional (2D) materials, such as graphene—a single layer of carbon atoms in a hexagonal lattice—exhibit unique properties due to their thinness and high surface area. Graphene’s exceptional electronic properties, related to relativistic-like Dirac electrons and strong light-matter interactions, make it promising for nonlinear optical applications, including ultrafast photonics, optical modulators, saturable absorbers in ultrafast lasers, and quantum optics.

Dr. Habib Rostami, from the Department of Physics at the University of Bath, has co-authored pioneering research published in Advanced Science. This study involved an international collaboration between an experimental team at Friedrich Schiller University Jena in Germany and theoretical teams at the University of Pisa in Italy and the University of Bath in the UK. The research aimed to investigate the ultrafast opto-electronic and thermal tuning of nonlinear optics in graphene.

This study discovers a new way to control high-harmonic generation in a graphene-based field-effect transistor. The team investigated the impact of lattice temperature, electron doping, and all-optical ultrafast tuning of third-harmonic generation in a hexagonal boron nitride-encapsulated graphene opto-electronic device. They demonstrated up to 85% modulation depth along with gate-tuneable ultrafast dynamics, a significant improvement over previous static tuning. Furthermore, by changing the lattice temperature of graphene, the team could enhance the modulation of its optical response, achieving a modulation factor of up to 300%. The experimental fabrication and measurement took place at Friedrich Schiller University Jena. Dr. Rostami played a crucial role in the study by crafting theoretical models. These models were developed in collaboration with another theory team at the University of Pisa to elucidate new effects observed in graphene.

Researchers at the UChicago Pritzker School of Molecular Engineering (UChicago PME) have realized a new design for a superconducting quantum processor, aiming at a potential architecture for the large-scale, durable devices the quantum revolution demands.

Unlike the typical quantum chip design that lays the information-processing qubits onto a 2D grid, the team from the Cleland Lab has designed a modular quantum processor comprising a reconfigurable router as a central hub. This enables any two qubits to connect and entangle, where in the older system, qubits can only talk to the qubits physically nearest to them.

“A quantum computer won’t necessarily compete with a classical computer in things like memory size or CPU size,” said UChicago PME Prof. Andrew Cleland.

Current laser technologies for the extended short-wave infrared (SWIR) spectral range rely on expensive and complex materials, limiting their scalability and affordability. To address these challenges, ICFO researchers have presented a novel approach based on colloidal quantum dots in an Advanced Materials article. The team managed to emit coherent light (a necessary condition to create lasers) in the extended SWIR range with large colloidal quantum dots made of lead sulfide (PbS).

This new CQD-based technology offers a solution to the aforementioned challenges while maintaining compatibility with silicon CMOS platforms (the technology used for constructing integrated circuit chips) for on-chip integration.

Their PbS colloidal quantum dots are the first semiconductor lasing material to cover such a broad wavelength range. Remarkably, the researchers accomplished this without altering the dots’ chemical composition. These results pave the way towards the realization of more practical and compact colloidal quantum dots lasers.

The search for quantum gravity has gone on for 100 years, but it is not the only unification challenge in physics. Many of us believe that one day there will be a unification theory—a theory that will reconcile many divergent physical theories.

Our new article published in Physica Scripta brings new hope that such a theory exists. It demonstrates that the use of a certain mathematical object called Alena Tensor reconciles various physical theories, including general relativity, electrodynamics, quantum mechanics and continuum mechanics. Will this finally allow scientists to unify descriptions used in physics?

Researchers have developed a tiny, room-temperature device that creates a special type of structured light called radially polarized photons, which are highly useful for secure communication, advanced imaging, and precision optical tools.

By carefully designing and positioning a quantum dot within a nanoantenna, they achieved high-quality light with more than 93% polarization purity. This breakthrough helps improve the efficiency and practicality of devices that use structured light, paving the way for advancements in communication and optical technology.

A team led by Prof. Ronen Rapaport from the Racah School of Physics at The Hebrew University of Jerusalem has developed the new device that produces radially polarized photons at room temperature. This advancement offers new possibilities for both classical and quantum communication technologies.

Present-day liquid-state lasers are based on organic dyes. Here we demonstrate an alternative class of liquid lasers that use solutions of colloidal quantum dots (QDs). Previous efforts to realize such devices have been hampered by the fast non-radiative Auger recombination of multicarrier states required for optical gain. Here we overcome this challenge by using type-(I + II) QDs, which feature a trion-like optical gain state with strongly suppressed Auger recombination. When combined with a Littrow optical cavity, static (non-circulated) solutions of these QDs exhibit stable lasing tunable from 634 nm to 575 nm. These results indicate the feasibility of technologically viable dye-like QD lasers that exhibit broad spectral tunability and, importantly, provide stable operation without the need for a circulation system—a standard attribute of traditional dye lasers. The latter opens the door to less complex and more compact devices that can be readily integrated with various optical and electro-optical systems. An additional advantage of these lasers is the wide range of potentially available wavelengths that can be selected by controlling the composition, size and structure of the QDs.

Liquid lasers based on solutions of colloidal quantum dots exhibit a trion-like optical gain state with suppressed Auger recombination, which combined with a Littrow optical cavity enables stable and tunable liquid-state lasing.

Researchers have set a new record for quantum entanglement — bringing reliable quantum computers a step closer to reality. The scientists successfully entangled 24 “logical qubits” — low-error quantum bits of information created by combining multiple physical qubits. This is the highest number ever achieved to date.

They also demonstrated that logical qubits can maintain error correction as the number of qubits increases, a crucial step toward larger, more fault-tolerant quantum systems. The researchers detailed their work in a study published Nov. 18 on the preprint database arXiv.

They say beauty is in the eye of the beholder – and for physicists, beauty is in numbers.

Pedro Vieira, Clay Riddell Dirac Chair in Theoretical Physics at Perimeter Institute, is currently teaching a non-credit minicourse about ‘beautiful’ papers in physics. The course alternates between lectures on nine influential papers and student-led presentations about how these monumental papers influenced physics.

This is Vieira’s second time running the course and his first time offering it at Perimeter. He says the course is a way to cover spectacular papers while helping students understand the language of quantum field theory.