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Category: quantum physics – Page 18

‘Superconducting dome’ hints at high-temperature superconductivity in thin nickelate films

Superconductivity is a quantum state of matter characterized by an electrical resistance of zero and the expulsion of magnetic fields at low temperatures below a critical point. Superconductors, materials in which this state occurs, have proved to be highly advantageous for the development of various technologies, including medical imaging devices, particle accelerators and quantum computers.

While superconductivity typically only occurs at extremely low temperatures, recent studies showed that in some materials it can arise at higher temperatures. These unconventional superconducting materials are referred to as high-temperature (high-Tc) superconductors.

Researchers at the National Laboratory of Solid-State Microstructures and Nanjing University recently gathered hints of high-Tc superconductivity in a thin film nickelate, a material that contains nickel and oxygen arranged in a thin layered crystal structure. Their paper, published in Physical Review Letters, maps the evolution of physical states in these materials under different conditions, unveiling a so-called “superconducting dome” in this phase diagram, which is associated with high-Tc superconductivity.

This new blood test could detect cancer before it shows up on scans

A new CRISPR-powered light sensor can detect the faintest molecular signs of cancer in a drop of blood. A new light-based sensor can spot incredibly tiny amounts of cancer biomarkers in blood, raising the possibility of earlier and simpler cancer detection. The technology merges DNAnanotechnology, CRISPR, and quantumdots to generate a clear signal from just a few molecules. In lung cancer tests, it worked even in real patient serum samples. Researchers hope it could eventually power portable blood tests for cancer and other diseases.

Scientists have designed a powerful light based sensor capable of detecting extremely small amounts of cancer biomarkers in blood. The innovation could eventually allow doctors to identify early warning signs of cancer and other diseases through a routine blood draw.

Biomarkers such as proteins, fragments of DNA, and other molecules can signal whether cancer is present, how it is progressing, or a person’s risk of developing it. The difficulty is that in the earliest stages of disease, these markers exist in extremely low concentrations, making them hard to measure with conventional tools.

The Observer Effect in Everyday Life

Daily reflection is a way to apply this principle in our everyday lives. It shines a spotlight on the behavior itself. And when behavior is observed consistently, it solidifies into neural pathways in the brain. We start behaving differently, not because someone else is judging us, but because we are measuring ourselves. The simple act of asking ourselves reflective questions each day shapes the behaviors in our lives, which, in turn, make us the people who exhibit those behaviors.

Another principle from quantum theory, entanglement, might also be at play when we do daily reflection. Quantum entanglement describes how particles can become linked to one another so that a change in one results in a change in the other. In the same way, the effort we make to change in one part of our lives is rarely confined to that part. Instead, our behaviors extend outward and affect those in relationship to us and around us. For example, your attempt to speak in positive terms, rather than negative ones, can influence your colleagues at work. Your intention to control your emotional outbursts can affect your family. Your efforts to build positive relationships at work or in your community can change the dynamics of those relationships. And when you combine these intentions with daily reflection, you’re not only strengthening a positive personal trait within yourself, but also influencing the bigger, interpersonal systems around you.

Philosophers, physicians, and physicists are forever debating what consciousness is. Is who we are just a byproduct of biology and the brain’s physiology, or is who we are more fundamental and exists irrespective of the brain’s neural firing? We may never know. That said, one thing is true: Conscious awareness shapes who we are. Without reflection, behavior defaults to habit. With reflection, possibility re-enters the system. The practice of asking yourself daily reflective questions puts you in the role of an observer rather than an actor. And from there, you can be intentional about who you choose to be tomorrow.

New Tool for Sculpting Single Photons

Researchers can adjust the frequency and bandwidth of single photons inside an optical fiber, which will be useful for future quantum networks.

Future quantum technologies will require practical techniques for adjusting the frequencies and bandwidths of individual photons to optimize them for various purposes without losing the delicate quantum data that they carry. Now researchers have improved on previous technology and have shown how both properties can be tuned over a wide range inside a short length of standard optical fiber [1]. They expect that this technique will be more practical and effective than current alternatives and will find wide use in interfacing devices in future quantum computing and communications networks.

Photons are likely to provide the means for transmitting information within future quantum networks, but frequent changes to their properties will be required in order for them to carry out a diversity of tasks. For example, a trapped-ion quantum memory emits or absorbs photons at a specific visible wavelength with an extremely narrow bandwidth, which means that a photon with which it interacts must be produced as a relatively long light pulse. In contrast, a high-speed fiber-optic channel works best with infrared photons having much broader bandwidths, which require short light pulses.

Material previously thought to be quantum is actually a new, non-quantum state of matter

Magnetic materials in a quantum spin liquid phase are of great interest in the pursuit of exotic state of matter and quantum computation. But in the quantum realm, things are not always what they seem. A study, published in Science Advances and co-led by Rice University’s Pengcheng Dai, found that the material cerium magnesium hexalluminate (CeMgAl11 O19) was not actually in a quantum spin liquid phase despite evidence suggesting it was.

“The material had been classified as a quantum spin liquid due to two properties: observation of a continuum of states and lack of magnetic ordering,” said Bin Gao, co-first author and a research scientist at Rice. “But closer observation of the material showed that the underlying cause of these observations wasn’t a quantum spin liquid phase.”

A superradiant clock phase emerges when Rydberg atoms meet quantum light, simulations suggest

Rydberg atoms are atoms with one or more outer electrons excited to very high energy levels, which interact very strongly with each other. These atoms are widely used to run quantum simulations and develop quantum technologies, as they can give rise to exotic and rare phases of matter.

Researchers at Chongqing University and Chongqing Normal University have uncovered a new highly synchronized quantum phase, known as a superradiant clock (SRC) phase, which could emerge in a system comprised of Rydberg atoms trapped in a triangular lattice constructed with a highly tunable optical tweezer array.

This newly reported phase, outlined in a paper published in Physical Review Letters, could open new possibilities for the simulation of many-body quantum systems and for the creation of cutting-edge quantum optical devices.

Can thermal noise train a computer? A new framework points to low-power AI

What if the thermal noise that hinders the efficiency of both classical and quantum computers could, instead, be used as a power source? What if computers could make use of the noise instead of suppressing or overcoming it? These are the goals of a relatively new branch of computing known as thermodynamic computing. A collaboration between researchers at the Molecular Foundry and the National Energy Research Scientific Computing Center (NERSC), both U.S. Department of Energy (DOE) user facilities located at Lawrence Berkeley National Laboratory (Berkeley Lab), is bringing them closer to reality.

In a paper published in Nature Communications, the researchers have proposed a design and training framework for a type of thermodynamic computer that mimics a neural network, which could drastically reduce the energy requirements of machine learning.

Modern computing requires energy: a single Google search, for example, consumes enough energy to power a six-watt LED for three minutes. This is partly because computers must contend with thermal noise—that is, the vibration of charge carriers, mostly electrons, within electronically conductive materials. In classical computers, even the smallest devices, such as transistors and gates, operate at energy scales thousands of times larger than that of this vibration.

Neutrons reveal magnetic signatures of chiral phonons

Physicists in China have uncovered new evidence that chiral phonons and magnons can interact strongly inside magnetic crystals. Using neutron spectroscopy, a team led by Song Bao at Nanjing University mapped magnetic signatures linked to chiral phonons in a ferrimagnetic material, revealing a previously elusive relationship between lattice vibrations and magnetic excitations. Reported in Physical Review Letters, the results could help researchers better understand how heat, sound and spin interact in quantum materials.

Phonons are collective vibrations of atoms in a crystal lattice which carry quantized packets of sound and heat through a solid. As quasiparticles, they behave somewhat like particles moving through the material and can interact with other excitations. In some cases, phonons also exhibit chirality: where some property of a particle differs from its mirror image.

For phonons, chirality arises when ions move in circular motions as the lattice vibrates, which imparts both an angular momentum and a tiny magnetic moment, which rotates in a plane perpendicular to the phonon’s direction of travel. Crucially, however, the phonon’s properties will vary depending on whether this rotation is clockwise or anticlockwise.

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