Neutrinos have a quantum mechanical property called “flavor.” This flavor can transform as neutrinos move through space. A major challenge is to keep track of both the physical movement of the neutrinos and their change of flavor in astrophysical systems such as core-collapse supernovae and neutron star mergers. The complicated arrangement and large number of neutrinos in these systems make it nearly impossible to follow all or even a subset of the neutrinos.
A Chinese research team has achieved a significant milestone in quantum computing by successfully building a device that can simulate the movement of electrons within a solid-state material.
This research, published in the journal Nature, showcases the potential of quantum computers to surpass even the most powerful supercomputers.
Understanding electron behavior is crucial for scientific advancements, particularly in the fields of magnetism and high-temperature superconducting materials. These materials could revolutionize electricity transmission and transportation, leading to significant energy savings and technological progress.
However, a paper just published in Physical Review D by physicists from the University of Warsaw and the University of Oxford has shown that many of these prejudices were unfounded. Tachyons are not only not ruled out by the theory, but allow us to understand its causal structure better.
Motion at speeds beyond the speed of light is one of the most controversial issues in physics. Hypothetical particles that could move at superluminal speeds, called tachyons (from the Greek tachýs—fast, quick), are the “enfant terrible” of modern physics. Until recently, they were widely regarded as creations that do not fit into the special theory of relativity.
At least three reasons for the non-existence of tachyons within quantum theory were known so far. The first: the ground state of the tachyon field was supposed to be unstable, which would mean that such superluminal particles would form “avalanches.” The second: a change in the inertial observer was supposed to lead to a change in the number of particles observed in his reference system, yet the existence of, say, seven particles cannot depend on who is looking at them. The third reason: the energy of the superluminal particles could take on negative values.
Quantum computing, which uses the laws of quantum mechanics, can solve pressing problems in a broad range of fields, from medicine to machine learning, that are too complex for classical computers.
The quantum Hall effect (QHE) is one of the most notable discoveries in condensed matter physics, opening the door to topological physics. Extending QHE into three dimensions is an inspiring but challenging endeavor. This difficulty arises because the Landau levels in three dimensions extend into bands along the direction of the magnetic field, preventing the opening of bulk gaps.
A team of physicists at the Weizmann Institute of Science in Israel has successfully demonstrated the inverse Mpemba effect at the quantum level using single trapped ions. In their study, published in the journal Physical Review Letters, the group demonstrated the effect by trapping a strontium-88 ion coupled to an external thermal bath.
Superconductivity is a fascinating phenomenon, which allows a material to sustain an electrical current without any loss. This collective quantum behavior of matter only appears in certain conductors at temperatures far below ambient.
Physicists have struggled to understand the nature of time since the field began. But a new theoretical study suggests time could be an illusion woven at the quantum level.
Google’s Sycamore quantum computer was the first to demonstrate quantum supremacy – solving calculations that would be unfeasible on a classical computer – but now ordinary machines have pulled ahead again.
Engineers at EPFL have developed a device capable of transforming heat into electrical voltage efficiently at temperatures even colder than those found in outer space. This breakthrough could significantly advance quantum computing technologies by addressing a major obstacle.
To perform quantum computations, quantum bits (qubits) need to be cooled to temperatures in the millikelvin range (close to-273 degrees Celsius) to reduce atomic motion and minimize noise. However, the electronics used to control these quantum circuits generate heat, which is challenging to dissipate at such low temperatures. Consequently, most current technologies must separate the quantum circuits from their electronic components, resulting in noise and inefficiencies that impede the development of larger quantum systems beyond the laboratory.
Researchers in EPFL’s Laboratory of Nanoscale Electronics and Structures (LANES), led by Andras Kis, in the School of Engineering have now fabricated a device that not only operates at extremely low temperatures, but does so with efficiency comparable to current technologies at room temperature.