Lifeboat Foundation

A quantum bit inspired by Schrödinger’s cat can resist making errors for an unprecedentedly long time, which makes it a candidate for building less error-prone quantum computers.

By Karmela Padavic-Callaghan

A powerful new idea about how the laws of physics work could bring breakthroughs on everything from quantum gravity to consciousness, says researcher Chiara Marletto

By Chiara Marletto

Researchers succeeded in conducting an almost perfect quantum teleportation despite the presence of noise that usually disrupts the transfer of quantum state.

In teleportation, the state of a quantum particle, or qubit, is transferred from one location to another without sending the particle itself. This transfer requires quantum resources, such as entanglement between an additional pair of qubits. In an ideal case, the transfer and teleportation of the qubit state can be done perfectly. However, real-world systems are vulnerable to noise and disturbances — and this reduces and limits the quality of the teleportation.

Advancements in Noise-Resilient Teleportation.

Researchers have made a significant advancement in quantum computing by adapting a microwave circulator to precisely control the nonreciprocity between a qubit and a resonant cavity. This innovation not only enhances the control within quantum computers but also simplifies the theoretical models for future research.

Scientists led by the University of Massachusetts Amherst have adapted a device called a microwave circulator for use in quantum computers, allowing them for the first time to precisely tune the exact degree of nonreciprocity between a qubit, the fundamental unit of quantum computing, and a microwave-resonant cavity. The ability to precisely tune the degree of nonreciprocity is an important tool to have in quantum information processing.

In doing so, the team, including collaborators from the University of Chicago, derived a general and widely applicable theory that simplifies and expands upon older understandings of nonreciprocity so that future work on similar topics can take advantage of the team’s model, even when using different components and platforms. The research was published recently in Science Advances.

In the 1880s Heinrich Hertz discovered that a spark jumping between two pieces of metal emits a flash of light – rapidly oscillating electromagnetic waves – which can be picked up by an antenna. To honour his groundbreaking work, the unit of frequency was named “Hertz” in 1930. Hertz’s findings were later used by Guglielmo Marconi (Nobel Prize in Physics, 1909) to transmit information over long distances creating radiocommunication and revolutionizing wireless telegraphy – shaping the modern world until today.

Scientists from the Department of Physics and the Regensburg Center for Ultrafast Nanoscopy (RUN), University of Regensburg, have now been able to directly observe a quantum version of Hertz’s spark jumping between just two atoms by measuring the oscillogram of the light it emits with temporal precision faster than a single oscillation cycle of the lightwave. This new signal enabled achieving a long-sought goal: atomic spatial resolution in all-optical microscopy.

As an unprecedented communication channel with the quantum world, this signal could be crucial for the development of super-fast quantum technologies as it gives new insights into the processes happening on lengthscales of single atoms and timescales faster than a trillionth of a second.

The paper is published in the journal Physical Review X.

In the world of quantum computing and quantum simulation technology, there is a fundamental challenge when using neutral atoms: The lifetime of Rydberg atoms, which are the building blocks for quantum computing, is limited. But there is a promising solution: circular Rydberg states.

For the first time, the research team has succeeded in generating and capturing circular Rydberg atoms of an alkaline-earth metal in an array of optical tweezers.

“They just have to stay underneath the tip until the light field changes its direction to be able to return.” By looking at an atomically thin insulator—a material that resists electrons spreading—the physicists got a first glimpse of these ultrafast matter currents and can now look into previously hidden atomic-scale dynamics in insulating layers ubiquitous in electronics and photovoltaics.

These new results present a groundbreaking advance in optical microscopy, bringing it to the ultimate length and time scales simultaneously. Direct observation of ultrafast tunneling currents could enable unprecedented understanding of electronic dynamics in quantum materials and quantum platforms for computing and data storage.

NOTE furthermore opens the door to atomic-scale strong-field dynamics such as lightwave electronics. The discovery of this communication channel with the quantum world could, just like Hertz’s findings over 100 years ago, spark a revolution in information transfer. Moreover, it could be key to understanding the microscopic dynamics shaping the devices of tomorrow.

Since the discovery of quantum mechanics more than a hundred years ago, it has been known that electrons in molecules can be coupled to the motion of the atoms that make up the molecules. Often referred to as molecular vibrations, the motion of atoms act like tiny springs, undergoing periodic motion. For electrons in these systems, being joined to the hip with these vibrations means they are constantly in motion too, dancing to the tune of the atoms, on timescales of a millionth of a billionth of a second.

But all this dancing around leads to a loss of energy and limits the performance of organic molecules in applications like organic light emitting diodes (OLEDs), infrared sensors and fluorescent biomarkers used in the study of cells and for tagging diseases such as cancer cells.

Now, researchers using laser-based spectroscopic techniques have discovered ‘new molecular design rules’ capable of halting this molecular dance. Their results, reported in Nature (“Decoupling excitons from high-frequency vibrations in organic molecules”), revealed crucial design principles that can stop the coupling of electrons to atomic vibrations, in effect shutting down their hectic dancing and propelling the molecules to achieve unparalleled performance.

Can we address mysteries of quantum mechanics by supposing that properties of objects long considered to have an independent existence are actually determined solely in relation to other objects or observers?

This program is part of the Big Ideas series, supported by the John Templeton Foundation.

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