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Category: quantum physics – Page 2

Terahertz instead of gigahertz — quantum material speeds up transistor switching by 1000 times

Researchers from Northeastern University in the United States have found a way to speed up electronics by a thousand times by replacement of silicon chips on quantum materials.

It is noted, that the new technology, through controlled heating and cooling, allows the quantum material to switch between the state of a conductor and an insulating material almost instantly. According to the researchers, such materials can replace silicon and lead to the emergence of electronic devices that are much faster and smaller.

«Processors currently operate in gigahertz. The speed of change that this will provide will allow you to move to terahertz», — explains the lead author of the study, professor of physics Alberto de la Torre.

Quantum Dots For Reliable Quantum Key Distribution

Making the exchange of a message invulnerable to eavesdropping doesn’t strictly require quantum resources. All you need to do is to encrypt the message using a one-use-only random key that is at least as long as the message itself. What quantum physics offers is a way to protect the sharing of such a key by revealing whether anyone other than sender and recipient has accessed it.

Imagine that a sender (Alice) wants to send a message to a recipient (Bob) in the presence of an eavesdropper (Eve). First, Alice creates a string of random bits. According to one of the most popular quantum communication protocols, known as BB84, Alice then encodes each bit in the polarization state of an individual photon. This encoding can be performed in either of two orientations, or “bases,” which are also chosen at random. Alice sends these photons one at a time to Bob, who measures their polarization states. If Bob chooses to measure a given photon in the basis in which Alice encoded its bit, Bob’s readout of the bit will match that of Alice’s. If he chooses the alternative basis, Bob will measure a random polarization state. Crucially, until Alice and Bob compare their sequence of measurement bases (but not their results) over a public channel, Bob doesn’t know which measurements reflect the bits encoded by Alice. Only after they have made this comparison—and excluded the measurements made in nonmatching bases—can Alice and Bob rule out that eavesdropping took place and agree on the sequence of bits that constitutes their key.

The efficiency and security of this process depend on Alice’s ability to generate single photons on demand. If that photon-generation method is not reliable—for example, if it sometimes fails to generate a photon when one is scheduled—the key will take longer to share. If, on the other hand, the method sometimes generates multiple photons simultaneously, Alice and Bob run the risk of having their privacy compromised, since Eve will occasionally be able to intercept one of those extra photons, which might reveal part of the key. Techniques for detecting such eavesdropping are available, but they involve the sending of additional photons in “decoy states” with randomly chosen intensities. Adding these decoy states, however, increases the complexity of the key-sharing process.

Quantum protocol achieves Heisenberg-limited measurement precision with robust spin states

Researchers from the National University of Singapore (NUS) have achieved exciting progress in quantum metrology, a field that harnesses quantum effects to make measurements with unprecedented accuracy. Their newly developed protocol could potentially benefit emerging technologies such as navigation and sensing of extremely weak signals.

Quantum metrology exploits the unique properties of to achieve sensitivities far exceeding classical limits. Pushing beyond the so-called standard quantum limit (SQL) to reach the ultimate Heisenberg limit (HL) typically requires highly entangled quantum states, such as Greenberger–Horne–Zeilinger (GHZ) states. However, these states are extremely challenging to generate, maintain, and measure, as they are highly susceptible to and readout errors, which are major obstacles for practical deployment.

Led by Professor Gong Jiangbin from the Department of Physics at the NUS Faculty of Science, the research team has developed a novel strategy that eliminates these roadblocks. Their method leverages quantum resonance dynamics in a periodically driven spin system, a well-studied model called the quantum kicked top.

Photon ‘time bins’ and signal stability show promise for practical quantum communication via fiber optics

Researchers at the Leibniz Institute of Photonic Technology (Leibniz IPHT) in Jena, Germany, together with international collaborators, have developed two complementary methods that could make quantum communication via fiber optics practical outside the lab.

One approach significantly increases the amount of information that can be encoded in a ; the other improves the stability of the quantum signal over long distances. Both methods rely on standard telecom components—offering a realistic path to secure through existing fiber networks.

From hospitals to government agencies and industrial facilities—anywhere must be kept secure—quantum communication could one day play a key role. Instead of transmitting electrical signals, this technology uses individual particles of light—photons—encoded in delicate quantum states. One of its key advantages: any attempt to intercept or tamper with the signal disturbs the , making eavesdropping not only detectable but inherently limited.

Quantum computers just beat classical ones — Exponentially and unconditionally

A research team has achieved the holy grail of quantum computing: an exponential speedup that’s unconditional. By using clever error correction and IBM’s powerful 127-qubit processors, they tackled a variation of Simon’s problem, showing quantum machines are now breaking free from classical limitations, for real.

Satyendra Nath Bose

Satyendra Nath Bose FRS, MP [ 1 ] (/ ˈ b oʊ s / ; [ 4 ] [ a ] 1 January 1894 – 4 February 1974) was an Indian theoretical physicist and mathematician. He is best known for his work on quantum mechanics in the early 1920s, in developing the foundation for Bose–Einstein statistics, and the theory of the Bose–Einstein condensate. A Fellow of the Royal Society, he was awarded India’s second highest civilian award, the Padma Vibhushan, in 1954 by the Government of India. [ 5 ] [ 6 ] [ 7 ]

The eponymous particles class described by Bose’s statistics, bosons, were named by Paul Dirac. [ 8 ] [ 9 ]

A polymath, he had a wide range of interests in varied fields, including physics, mathematics, chemistry, biology, mineralogy, philosophy, arts, literature, and music. He served on many research and development committees in India, after independence. [ 10 ] .