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Researchers from four universities in Germany have created the coldest temperature ever recorded in a lab38 trillionths of a degree warmer than absolute zero to be exact, according to their new work, recently published in the journal Physical Review Letters.

The bone-chilling temperature only persisted for a few seconds at the University of Bremen's Center for Applied Space Technology and Microgravity, but the breakthrough could have longstanding ramifications for our understanding of quantum mechanics.

That's because the closer we get to absolute zerothe lowest possible temperature that we could ever theoretically reach, as outlined by the laws of thermodynamicsthe more peculiarly particles, and therefore substances, act. Liquid helium, for instance, becomes a "superfluid" at significantly low temperatures, meaning that it flows without any resistance from friction. Nitrogen freezes at -210 degrees Celsius. At cool enough temperatures, some particles even take on wave-like characteristics.

Absolute zero is equal to 273.15 degrees Celsius, or -459.67 degrees Fahrenheit, but most commonly, it's measured as 0 Kelvins. This is the point at which "the fundamental particles of nature have minimal vibrational motion," according to ScienceDaily. However, it's impossible for scientists to create absolute zero conditions in the lab.

In this case, the researchers were studying wave properties of atoms when they came up with a process that could lower a system's temperature by slowing particles to virtually a total standstill. For several seconds, the particles held completely still, and the temperature lowered to an astonishing 38 picokelvins, or 38 trillionths of a degree above absolute zero. This temperature is so low that it's not even detectable with a regular thermometer of any kind. Instead, the temperature is based on the lack of kinetic movement of the particles.

The mechanism at play here is "a time-domain matter-wave lens system," according to the team's research paper. A matter wave is just what it sounds like: matter that is behaving like a wave. This is part of quantum physics, where everything we previously thought we knew gets a little wobbly upon close examination. In this case, scientists used an magnetic lens to shape a quantum gas, and used that to make a matter wave focus and behave in a particular way. A regular gas is made of a loose arrangement of discrete particles, but a quantum gas is no such predictable material. In this case, the quantum gas is a perplexing state of matter called a Bose-Einstein condensate.

The lens is "tuned" using careful excitation. Think of the lenses on a pair of glasses, where the bend is designed to focus closer or further away depending on the patient's eyes. For this experiment, the scientists tuned the focus to literally infinity. Within the subset of quantum physics known as optics, this means the quantum gas confines the passing particles until they pass one at a time and at an astonishingly slow speed.

"By combining an excitation of a Bose-Einstein condensate (BEC) with a magnetic lens, we form a time-domain matter-wave lens system," the researchers write. "The focus is tuned by the strength of the lensing potential. By placing the focus at infinity, we lower the total internal kinetic energy of a BEC to 38pK."

The researchers, from the University of Bremen, Leibniz University Hannover, the Humboldt University of Berlin, and the Johannes Gutenberg University Mainz, say they envision future researchers making the particles go even slower, with a top potential "weightlessness" period of up to 17 seconds.

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Coldest Temperature Ever Recorded | What Is Absolute Zero? - Popular Mechanics

When you come to the fork in the road, take it. Yogi Berra

For cryptologists, Yogi Berras words have perhaps never rang more true. As a future with quantum computing approaches, our internet and stored secrets are at risk. The tried-and-true encryption mechanisms that we use every day, like Transport Layer Security (TLS) and Virtual Private Networks (VPN), could be cracked and exposed by a hacker equipped with a large enough quantum computer using Shors algorithm, a powerful algorithm with exponential speed over classical algorithms. The result?The security algorithms we use today that would take roughly 10 billion years to decrypt could take as little as 10 seconds. To prevent this, its imperative that we augment our security protocols, and we have two options to choose from: one using physics as its foundation, or one using math our figurative fork in the road.

To understand how to solve the impending security threats in a quantum era, we need to first understand the fundamentals of our current encryption mechanism. The most commonly used in nearly all internet activities TLS is implemented anytime someone performs an online activity involving sensitive information, like logging into a banking app, completing a sale on an online retailer website, or simply checking email. It works by combining the data with a 32-byte key of random 1s and 0s in a complicated and specific way so that the data is completely unrecognizable to anyone except for the two end-to-end parties sending and receiving the data. This process is called public key encryption, and currently it leverages a few popular algorithms for key exchange, e.g., Elliptic curve Diffie-Hellman (ECDH) or RSA (each named after cryptologists,) each of which are vulnerable to quantum computers. The data exchange has two steps: the key exchange and the encryption itself. The encryption of the data with a secure key will still be safe, but the delivery of the key to unlock that information (key distribution) will not be secure in the future quantum era.

To be ready for quantum computers, we need to devise a new method of key distribution, a way to safely deliver the key from one end of the connection to the other.

Imagine a scenario wherein you and a childhood friend want to share secrets, but can only do so once you each have the same secret passcode in front of you (and there are no phones.) One friend has to come up with a unique passcode, write it down on a piece of paper (while maintaining a copy for themselves,) and then walk it down the block so the other has the same passcode. Once you and your friend have the shared key, you can exchange secrets (encrypted data) that even a quantum computer cannot read.

While walking down the block though, your friend could be vulnerable to the school bully accosting him or her and stealing the passcode, and we cant let this happen. What if your friend lives across town, and not just down the block? Or even more difficult in a different country? (And where is that secret decoder ring we got from a box of sugar-coated-sugar cereal we ate as kids?)

In a world where global information transactions are happening nonstop, we need a safe way of delivering keys no matter the distance. Quantum physics can provide a way to securely deliver shared keys quicker and in larger volume, and, most importantly, immune to being intercepted. Using fiber optic cables (like the ones used by telecommunications companies,) special Quantum Key Distribution (QKD) equipment can send tiny particles (or light waves) called photons to each party in the exchange of data. The sequence of the photons encapsulates the identity of the key, a random sequence of 1s and 0s that only the intended recipients can receive to construct the key.

Quantum Key Distribution also has a sort of built-in anti-hacker bonus. Because of the no-cloning theorem (which essentially states that by their very nature, photons cannot be cloned,) QKD also renders the identity of the key untouchable by any hacker. If an attacker tried to grab the photons and alter them, it would automatically be detected, and the affected key material would be discarded.

The other way we could choose to solve the security threats posed by quantum computers is to harness the power of algorithms. Although its true the RSA and ECDH algorithms are vulnerable to Shors algorithm on a suitable quantum computer, the National Institute of Standards and Technology (NIST) is working to develop replacement algorithms that will be safe from quantum computers as part of its post-quantum cryptography (PQC) efforts. Some are already in the process of being vetted, like ones called McEliece, Saber, Crystals-Kyber, and NTRU.

Each of these algorithms has its own strong and weak points that the NIST is working through. For instance, McEliece is one of the most trusted by virtue of its longstanding resistance to attack, but it is also handicapped by its excessively long public keys that may make it impractical for small devices or web browsing. The other algorithms, especially Saber, run very well on practically any device, but, because they are relatively new, the confidence level in them from cryptographers is still relatively low.

With such a dynamic landscape of ongoing efforts, there is promise that a viable solution will emerge in time to keep our data safe.

The jury is still out. We at Verizon and most of the world rely heavily on e-commerce to sell our products and encryption to communicate via email, messaging, and cellular voice calls.All of these need secure encryption technologies in the coming quantum era. But whether we choose pre-shared keys (implemented by the awesome photon) or algorithms, further leveraging mathematics, our communications software will need updating. And while the post quantum cryptography effort is relatively new, it is not clear which algorithms will withstand scrutiny from the cryptographic community. In the meantime, we continue to peer down each fork in the road to seek the best option to take.

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Quantum computing will break today's encryption standards - here's what to do about it - Verizon Communications

Metasurface of split-ring resonators, partially overlaid with 3D colourmaps showing the simulated electric-field distribution. High-momentum magnetoplasmons lead to the break-down of polaritons (blue spheres with photon energies in red). Credit: Urban Senica, ETH Zurich

Physicists from the University of Southampton and ETH Zrich have reached a new threshold of light-matter coupling at the nanoscale.

The international research, published recently in Nature Photonics, combined theoretical and experimental findings to establish a fundamental limitation of our ability to confine and exploit light.

The collaboration focused on photonic nano-antennas fabricated in ever reducing sizes on the top of a two-dimensional electron gas. The setup is commonly used in laboratories all over the world to explore the effect of intense electromagnetic coupling, taking advantage of the antennas ability to trap and focus light close to electrons.

Professor Simone De Liberato, Director of the Quantum Theory and Technology group at the University of Southampton, says: The fabrication of photonic resonators able to focus light in extremely small volumes is proving a key technology which is presently enabling advances in fields as different as material science, optoelectronics, chemistry, quantum technologies, and many others.

In particular, the focussed light can be made to interact extremely strongly with matter, making electromagnetism non-perturbative. Light can then be used to modify the properties of the materials it interacts with, thus becoming a powerful tool for material science. Light can be effectively woven into novel materials.

Scientists discovered that light could no longer be confined in the system below a critical dimension, of the order of 250nm in the sample under study, when the experiment started exciting propagating plasmons. This caused waves of electrons to move away from the resonator and spill the energy of the photon.

Experiments performed in the group of Professors Jrme Faist and Giacomo Scalari at ETH Zrich had obtained results that could not be interpreted with state-of-the-art understanding of light-matter coupling. The physicists approached Southamptons School of Physics and Astronomy, where researchers led theoretical analysis and built a novel theory able to quantitatively reproduce the results.

Professor De Liberato believes the newfound limits could yet be exceeded by future experiments, unlocking dramatic technological advances that hinge on ultra-confined electromagnetic fields.

Read Exploring the Quantitative Limits of LightMatter Coupling at the Nanoscale for more on this research.

Reference: Polaritonic nonlocality in lightmatter interaction by Shima Rajabali, Erika Cortese, Mattias Beck, Simone De Liberato, Jrme Faist and Giacomo Scalari, 9 August 2021, Nature Photonics.DOI: 10.1038/s41566-021-00854-3

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New Fundamental Limit of Trapping and Exploiting Light at the Nanoscale - SciTechDaily