Research at the Quantum Systems Accelerator has been steadily breaking new ground, quickening the pace toward flexible, stable quantum computers with capabilities well beyond those of today’s classical machines.
Category: quantum physics – Page 12
Decades-old mystery of AlCl dipole moment resolved
In a study that closes a long-standing knowledge gap in fundamental science, researchers Boerge Hemmerling and Stephen Kane at the University of California, Riverside, have successfully measured the electric dipole moment of aluminum monochloride (AlCl), a simple yet scientifically crucial diatomic molecule.
Their results, published in Physical Review A, have implications for quantum technologies, astrophysics, and planetary science. The paper is titled “Measurement of the electric dipole moment of AlCl by Stark-level spectroscopy.”
Until now, the dipole moment of AlCl was only estimated, with no experimental confirmation. The study’s precise measurement now replaces the theoretical predictions with solid experimental data.
No, Quantum Mechanics does Not Need Complex Numbers
No journal is perfect, and despite Nature being considered a high quality journal, I have recently come across a paper which is, to put it bluntly, is slop. It is a bit of slop easily debunkable by anyone who can do a tiny bit of linear algebra.
The paper is titled “Quantum theory based on real numbers can be experimentally falsified.” The entire paper is misleading because it presents a very specific representation of quantum mechanics based solely on real numbers, shows that it leads to different predictions than traditional quantum theory, and then concludes therefore complex numbers are a necessity for complex theory.
This is obviously false. A complex number is just two real numbers stitched together. Classical computers can’t operate on complex numbers and so they just break them apart into two real floating point numbers and do the equivalent calculations in that form, but then display it as a complex number, and they can reproduce anything you can reproduce using complex numbers. Indeed, my quantum computer simulator I had put together myself uses its own complex matrix library for linear algebra, and each element of the matrix is specified by two real numbers.
30 Space Phenomena That Are Still a Mystery
Dark matter constitutes about 27% of the universe, yet it remains one of the greatest mysteries in cosmology. Unlike normal matter, it does not emit, absorb, or reflect light, making it invisible and detectable only through its gravitational effects. Understanding dark matter is crucial for explaining galaxy formation and cosmic structure.
Accounting for approximately 68% of the universe, dark energy is a hypothetical form of energy proposed to explain the accelerated expansion of the universe. Its nature and properties remain unclear. Dark energy challenges our understanding of gravity and the ultimate fate of the cosmos.
Black holes are regions with a gravitational pull so strong that nothing, not even light, can escape. While we have theories describing their behavior, their interiors remain shrouded in mystery. The existence of black holes challenges the boundaries of our understanding of physics, including general relativity and quantum mechanics.
Oxford physicists recreate extreme quantum vacuum effects
Physicists at the University of Oxford have successfully simulated how light interacts with empty space – a phenomenon once thought to belong purely to the realm of science fiction. The simulations recreated a bizarre phenomenon predicted by quantum physics, where light appears to be generated from darkness. The findings pave the way for real-world laser facilities to experimentally confirm bizarre quantum phenomena. The results have been published in Communications Physics.
Using advanced computational modelling, a research team led by the University of Oxford, working in partnership with the Instituto Superior Técnico in the University of Lisbon, has achieved the first-ever real-time, three-dimensional simulations of how intense laser beams alter the ‘quantum vacuum’ – a state once assumed to be empty, but which quantum physics predicts is full of virtual electron-positron pairs.
Excitingly, these simulations recreate a bizarre phenomenon predicted by quantum physics, known as vacuum four-wave mixing. This states that the combined electromagnetic field of three focused laser pulses can polarise the virtual electron-positron pairs of a vacuum, causing photons to bounce off each other like billiard balls – generating a fourth laser beam in a ‘light from darkness’ process. These events could act as a probe of new physics at extremely high intensities.
Quantum navigation device uses atoms to measure acceleration in 3D
In a new study, physicists at the University of Colorado Boulder have used a cloud of atoms chilled down to incredibly cold temperatures to simultaneously measure acceleration in three dimensions—a feat that many scientists didn’t think was possible.
The device, a new type of atom “interferometer,” could one day help people navigate submarines, spacecraft, cars and other vehicles more precisely.
“Traditional atom interferometers can only measure acceleration in a single dimension, but we live within a three-dimensional world,” said Kendall Mehling, a co-author of the new study and a graduate student in the Department of Physics at CU Boulder. “To know where I’m going, and to know where I’ve been, I need to track my acceleration in all three dimensions.”
Quantum mechanics provide truly random numbers on demand
Randomness is incredibly useful. People often draw straws, throw dice or flip coins to make fair choices. Random numbers can enable auditors to make completely unbiased selections. Randomness is also key in security; if a password or code is an unguessable string of numbers, it’s harder to crack. Many of our cryptographic systems today use random number generators to produce secure keys.
But how do you know that a random number is truly random?
Classical computer algorithms can only create pseudorandom numbers, and someone with enough knowledge of the algorithm or the system could manipulate it or predict the next number. An expert in sleight of hand could rig a coin flip to guarantee a heads or tails result. Even the most careful coin flips can have bias; with enough study, their outcomes could be predicted.
Scientists achieve shortest hard X-ray pulses to date
Once only a part of science fiction, lasers are now everyday objects used in research, health care and even just for fun. Previously available only in low-energy light, lasers are now available in wavelengths from microwaves through X-rays, opening a range of different downstream applications.
In a study published in Nature, an international collaboration led by scientists at the University of Wisconsin–Madison has generated the shortest hard X-ray pulses to date through the first demonstration of strong lasing phenomena.
The resulting pulses can lead to several potential applications, from quantum X-ray optics to visualizing electron motion inside molecules.