Part of the team behind the invention. From left: Peter Lodahl, Anders Sørensen, Vasiliki Angelopoulou, Ying Wang, Alexey Tiranov, Cornelis van Diepen. Photo: Ola J. Joensen.

Quantum physicists make major nanoscopic advance

In a new breakthrough, researchers have solved a problem that has caused quantum researchers headaches for years. The researchers can now control two quantum light sources rather than one. Trivial as it may seem to those uninitiated in quantum, this colossal breakthrough allows researchers to create a phenomenon known as quantum mechanical entanglement. This in turn, opens new doors for companies and others to exploit the technology commercially.

Figure 1. Left: Experimental measurement of colloidal particles driven in a thin microfluidic channel. The particles form stable, hydrodynamically coupled pairs moving at the same velocity (arrows). These pairs are the fundamental quasiparticles of the system. Right: Simulation of a hydrodynamic crystal, showing a quasiparticle pair (leftmost yellow and orange particles) propagating in a hydrodynamic crystal, leaving behind a supersonic Mach cone of excited quasiparticles. Colors denote the magnitude of the pair excitation, and the white background denotes their velocity (see movie).

Scientists observe ‘quasiparticles’ in classical systems

Quasiparticles — long-lived particle-like excitations — are a cornerstone of quantum physics, with famous examples such as Cooper pairs in superconductivity and, recently, Dirac quasiparticles in graphene. Now, researchers have discovered quasiparticles in a classical system at room temperature: a two-dimensional crystal of particles driven by viscous flow in a microfluidic channel. Coupled by hydrodynamic forces, the particles form stable pairs — a first example of classical quasiparticles, revealing deep links between quantum and classical dissipative systems.

Setup and tuning range of parameters

Steady-state Peierls transition in nanotube quantum simulator

Quantum dots placed along a vibrating nanotube provide a quantum simulation platform that can directly address the electron-phonon interaction. This offers promising prospects for the search of new quantum materials and the study of strong […]

The Carnot cycle is a general model of energy production that can be applied to any thermal energy source. Devised by the pioneering French physicist Sadi Carnot in 1824, when only steam engines were available, it can equally well be applied today to nuclear or solar power plants.

No ‘second law of entanglement’ after all

When two microscopic systems are entangled, their properties are linked to each other irrespective of the physical distance between the two. Manipulating this uniquely quantum phenomenon is what allows for quantum cryptography, communication, and computation. While parallels have been drawn between quantum entanglement and the classical physics of heat, new research demonstrates the limits of this comparison. Entanglement is even richer than we have given it credit for.

The thermodynamics of quantum computing

The thermodynamics of quantum computing

Heat and computers do not mix well. If computers overheat, they do not work well or may even crash. But what about the quantum computers of the future? These high-performance devices are even more sensitive to heat. This is because their basic computational units — quantum bits or “qubits” — are based on highly-sensitive units, some of them individual atoms, and heat can be a crucial interference factor.

Non-linear Boson Sampling

Non-linear Boson Sampling

Boson Sampling is a task that is conjectured to be computationally hard for a classical computer, but which can be efficiently solved by linear-optical interferometers with Fock state inputs. Significant advances have been reported in […]

New quantum computing architecture could be used to connect large-scale devices

New quantum computing architecture to connect large-scale devices

Researchers have demonstrated an architecture that can enable high fidelity and scalable communication between superconducting quantum processors. Their technique can generate and route photons, which carry quantum information, in a user-specified direction. This method could be used to develop a large-scale network of quantum processors that could efficiently communicate with one another.

Schematic levels of the 171Yb+ atomic sensor and the experimental setup

A neural network assisted 171Yb+ quantum magnetometer

A versatile magnetometer must deliver a readable response when exposed to target fields in a wide range of parameters. Researchers have experimentally demonstrated that the combination of 171Yb+ atomic sensors with adequately trained neural networks enables […]

Illustration of cooling collective Bogoluibov modes by applying multiple tweezers per particle

Tuneable Gaussian entanglement in levitated nanoparticle arrays

Optically levitated nanoparticles emerged as an interesting platform for probing fundamental physics. Quantum control of their motion (including potential shaping) predisposes them for emulating various physical systems and studying quantum phenomena with massive objects. Extending […]

Illustration of the magneto-mechanical resonator array used in the experiment. Image credit: Gengming Liu

Researchers show a new way to induce useful defects using invisible material properties

Much of modern electronic and computing technology is based on one idea: add chemical impurities, or defects, to semiconductors to change their ability to conduct electricity. These altered materials are then combined in different ways to produce the devices that form the basis for digital computing, transistors, and diodes. Indeed, some quantum information technologies are based on a similar principle: adding defects and specific atoms within materials can produce qubits, the fundamental information storage units of quantum computing.

Professor Michael Hecht and co-author on the quantum dot research Yueyu Yao in Frick Laboratory. Photo by Jesse Condon

Quantum dots at room temp, using lab-designed protein

Quantum dots are normally made in industrial settings with high temperatures and toxic, expensive solvents — a process that is neither economical nor environmentally friendly. But researchers have now pulled off the process at the bench using water as a solvent, making a stable end-product at room temperature. Their work opens the door to making nanomaterials in a more sustainable way by demonstrating that protein sequences not derived from nature can be used to synthesize functional materials.

In Borromean rings, each circle holds the pattern together by passing through the other two circles. Image: Alexandr Kakinen.

A peculiar protected structure links Viking knots with quantum vortices

Scientists have shown how three vortices can be linked in a way that prevents them from being dismantled. The structure of the links resembles a pattern used by Vikings and other ancient cultures, although this study focused on vortices in a special form of matter known as a Bose-Einstein condensate. The findings have implications for quantum computing, particle physics and other fields.

Artistic representation of a curved space using the example of the Heidelberg experiment. Curving the spacetime of the universe requires huge masses or energies. For the effective spacetime generated by a Bose-Einstein condensate, however, the research team only manipulated the density distribution of the condensate. In addition, expansion was simulated by adjusting the interaction between the atoms. | © Celia Viermann

Curved spacetime in the lab

In a laboratory experiment, researchers have succeeded in realizing an effective spacetime that can be manipulated. In their research on ultracold quantum gases, they were able to simulate an entire family of curved universes to investigate different cosmological scenarios and compare them with the predictions of a quantum field theoretical model.