Phys.org May 10, 2023 Temporal modes (TMs), an encoding basis based on the time-frequency degree of freedom of photons, represent one of the most promising high-dimensional alphabets. TM-based quantum communication has until now been limited to a two-dimensional space due to the lack of a suitable decoder. However, quantum communication protocols based on single-photon TMs require suitable multichannel decoders. Researchers in Germany have demonstrated a new device that facilitates demultiplexing of high-dimensional TMs of single photons, and implemented a complete five-dimensional decoder that enables TM-based high-dimensional quantum key distribution. They showed that it is possible to scale the presented decoder […]
Tag Archives: quantum cryptography
Microlaser chip adds new dimensions to quantum communication
Phys.org November 21, 2022 In quantum communications with qubits, the superposition makes it so a quantum pulse cannot be copied. However, with only two levels of superposition, qubits have limited storage space and low tolerance for interference. An international team of researchers (USA – University of Pennsylvania, Duke University, City University of New York, Spain, Italy) has created a chip that outstrips the security and robustness of existing quantum communications hardware. The device’s four-level qudits enable significant advances in quantum cryptography, raising the maximum secrete key rate for information exchange from 1 bit per pulse to 2 bits per pulse. […]
Chaining atoms together yields quantum storage
Phys.org February 16, 2022 Researchers at Caltech have developed an approach for quantum storage that relies on nuclear spins oscillating collectively as a spin wave. This collective oscillation effectively chains up several atoms to store information. They utilized a qubit made from an ion of ytterbium and embedded the ion in a transparent crystal of yttrium orthovanadate (YVO4) and manipulated its quantum states via a combination of optical and microwave fields. The Yb qubit was used to control the nuclear spin states of multiple surrounding vanadium atoms in the crystal. A unique feature of this system is the pre-determined placement […]
Five emerging cyber-threats to worry about in 2019
MIT Technology Review January 4, 2019 According to experts in the field we going to see more mega-breaches and ransomware attacks in 2019. Besides planning to deal with established risks, like threats to web-connected consumer devices and critical infrastructure, cyber-defenders should be paying attention to new threats, too. Here are some that should be on watch lists: Exploiting AI-generated fake video and audio, Poisoning AI defenses, hacking smart contracts, Breaking encryption using quantum computers, Attacking from the computing cloud. A recent report by NAS from a group of US quantum experts urges organizations to start adopting new and forthcoming kinds of […]
Approximate quantum cloning: The new way of eavesdropping in quantum cryptography
Physorg February 20, 2018 Uncertainty at the quantum scale makes exact cloning of quantum states impossible. Yet, they may be copied in an approximate way using probabilistic quantum cloning. Continuing previous work, researchers in China showed that if an independent subset cannot be expressed as the superposition of the other states in the set, then these dependent states can be partially cloned. Cloning operation allows scientists to make many copies of the output of computations—which take the form of unitary operations. These can, in turn, be used as input and fed into various further processes. Cloning also has applications in […]