The new big thing in magnetics is altermagnetism, a form of magnetism that promises to power the next generation of electronics. Unlike ferromagnets, like a fridge magnet, where all internal atomic spins align to create a strong magnetic field, altermagnets have no net magnetic pull (strongly magnetic on the inside, but appears non-magnetic on the outside). This is similar to antiferromagnets where internal spins cancel each other out. However, altermagnets retain powerful internal properties that could let them carry and control information more efficiently than traditional magnets.
Because this magnetism has a zero net pull, it is hard to detect using standard measurement tools. In two new papers, researchers detail how they have developed X-ray techniques to map and measure different aspects of an altermagnet’s internal structure.
Electromagnetic waves with frequencies between microwave and infrared light, also known as terahertz radiation, are leveraged by many existing technologies, including various imaging tools and wireless communication systems. Despite their widespread use, generating strong and continuous terahertz signals using existing electronics is known to be challenging.
To reliably generate terahertz signals, engineers often rely on frequency multipliers, electronic circuits that can distort an input signal, to generate an output signal with a desired frequency. Some of these circuits are based on Schottky barrier diodes, devices in which the junction between a metal and semiconductor form a one-way electrical contact.
While some frequency multipliers based on Schottky barrier diodes have achieved promising results, devices based on individual diodes can only handle a limited amount of energy. To increase the energy they can manage, engineers can use several diodes arranged in a chain. However, even this approach can have its limitations, as the distribution of the electromagnetic field between the diodes in a chain often becomes uneven.
In the world of optics, tiny structures called microcavities—often no wider than a human hair—play a crucial role in technologies ranging from lasers to sensors.
These microscopic resonators trap light, allowing it to circulate millions of times within their boundaries. When they are perfectly shaped, light inside them moves in smooth, circular paths. But when their symmetry is slightly disturbed, the light begins to behave unpredictably, following chaotic routes that can lead to surprising effects like one-way laser emission or stronger light–matter interactions.
Until now, most research on this chaotic behavior has focused on flat, two-dimensional microcavities. These are easier to study because their shape can be seen and measured under a microscope. But truly three-dimensional (3D) microcavities—where deformation occurs in all directions—have remained largely unexplored. Their internal geometry is difficult to capture without cutting or damaging the sample, making it hard to understand how light behaves inside them.
Electromagnetic waves with frequencies between microwave and infrared light, also known as terahertz radiation, are leveraged by many existing technologies, including various imaging tools and wireless communication systems. Despite their widespread use, generating strong and continuous terahertz signals using existing electronics is known to be challenging.
To reliably generate terahertz signals, engineers often rely on frequency multipliers, electronic circuits that can distort an input signal, to generate an output signal with a desired frequency. Some of these circuits are based on Schottky barrier diodes, devices in which the junction between a metal and semiconductor form a one-way electrical contact.
While some frequency multipliers based on Schottky barrier diodes have achieved promising results, devices based on individual diodes can only handle a limited amount of energy. To increase the energy they can manage, engineers can use several diodes arranged in a chain. However, even this approach can have its limitations, as the distribution of the electromagnetic field between the diodes in a chain often becomes uneven.
A proposed experiment may deliver evidence for the emission or absorption of gravitons—an advance that might one day enable gravity to be controlled much like electromagnetism is today.
A major milestone in human development was the transition from passively observing electromagnetic phenomena, such as electric discharges and magnetism, to actively manipulating them. This shift led to a plethora of applications—from power plants to modern electronics. The exquisite control of electromagnetic fields and of their interaction with matter has also yielded deep insights into the fundamental laws of nature, allowing us to test modern theories with remarkable precision. Now Ralf Schützhold of the Helmholtz-Zentrum Dresden-Rossendorf in Germany argues that a similar turning point may be reached for gravity [1]. His approach for manipulating gravity relies on experiments that can control the emission or absorption of gravitons, the hypothetical elementary particles mediating the gravitational interaction in a quantized theory of gravity.
Could global positioning systems become more precise and provide more accurate details on distances for users to get from point A to point B?
A study by University of Rhode Island assistant physics professor Wenchao Ge in collaboration with Kurt Jacobs, a physicist of quantum tech with the U.S. Army, which was recently published by Physical Review Letters, may lead to more enhanced quantum sensing and make such detection data more definitive.
Ge’s study, “Heisenberg-Limited Continuous-Variable Distributed Quantum Metrology with Arbitrary Weights” published by in September, looked at networked quantum sensing, which explores advanced sensor technology in an entangled network that could improve accuracy on how to measure, navigate and explore the world, such as by sensing changes in motion, and electric or magnetic fields.
It’s not only fast enough to watch light move, it’s fast enough to see the past.