Lifeboat Foundation

Quantum physics is strange. At least, it is strange to us, because the rules of the quantum world, which govern the way the world works at the level of atoms and subatomic particles (the behavior of light and matter, as the renowned physicist Richard Feynman put it), are not the rules that we are familiar with — the rules of what we call “common sense.”

The quantum rules, which were mostly established by the end of the 1920s, seem to be telling us that a cat can be both alive and dead at the same time, while a particle can be in two places at once. But to the great distress of many physicists, let alone ordinary mortals, nobody (then or since) has been able to come up with a common-sense explanation of what is going on. More thoughtful physicists have sought solace in other ways, to be sure, namely coming up with a variety of more or less desperate remedies to “explain” what is going on in the quantum world.

These remedies, the quanta of solace, are called “interpretations.” At the level of the equations, none of these interpretations is better than any other, although the interpreters and their followers will each tell you that their own favored interpretation is the one true faith, and all those who follow other faiths are heretics. On the other hand, none of the interpretations is worse than any of the others, mathematically speaking. Most probably, this means that we are missing something. One day, a glorious new description of the world may be discovered that makes all the same predictions as present-day quantum theory, but also makes sense. Well, at least we can hope.

Researchers have demonstrated a quantum sensor that can power itself using sunlight and an ambient magnetic field, an achievement that could help reduce the energy costs of this energy-hungry technology.

No longer the realm of science fiction, quantum sensors are today used in applications ranging from timekeeping and gravitational-wave detection to nanoscale magnetometry [1]. When making new quantum sensors, most researchers focus on creating devices that are as precise as possible, which typically requires using advanced—energy-hungry—technologies. This high energy consumption can be problematic for sensors designed for use in remote locations on Earth, in space, or in Internet-of-Things sensors that are not connected to mains electricity. To reduce the reliance of quantum sensors on external energy sources, Yunbin Zhu of the University of Science and Technology of China and colleagues now demonstrate a quantum sensor that directly exploits renewable energy sources to get the energy it needs to operate [2].

Quantum effects play a hitherto unexpected role in creating instabilities in DNA – the so-called “molecule of life” that provides instructions for cellular processes in all living organisms. This conclusion, based on work by researchers at the University of Surrey in the UK, goes against long-held beliefs that quantum behaviour is not relevant in the wet, warm environment of cells, and could have far-reaching consequences for models of genetic mutation.

The two strands of the DNA double helix are linked together by hydrogen bonds between the DNA bases. There are typically four different bases, called Guanine (G), Cytosine ©, Adenine (A) and Thymine (T). In the standard configuration, A always bonds to T while C always bonds to G. However, if the protons (nuclei of the hydrogen atoms) that make up the bonds hop from one strand of DNA to the other then a genetic mutation can occur.

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Physicists are (temporarily) augmenting reality in order to crack the code of quantum systems.

Calculating the collective behavior of a molecule’s electrons is necessary to predict a material’s properties. Such predictions could one day help scientists create novel drugs or create materials with desirable qualities like superconductivity. The issue is that electrons may become ‘quantum mechanically’ entangled with one another, which means they can no longer be treated individually. For any system with more than a few particles, the entangled network of connections becomes outrageously difficult for even the most powerful computers to unravel directly.

Now, quantum physicists from the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland and the Flatiron Institute’s Center for Computational Quantum Physics (CCQ) in New York City have found a workaround. By adding extra “ghost” electrons in their computations that interact with the system’s actual electrons, they were able to simulate entanglement.

An international research team led by the Department of Microstructured Quantum Matter at the MPSD reports the first observation of switchable chiral transport in a structurally achiral crystal, the Kagome superconductor CsV₃Sb₅. Their work has been published in Nature.

Whether or not an object is indistinguishable from its mirror image has important consequences for its physical behavior. Say you watch a basketball player in a mirror. The ball, the player and their surroundings are, at first glance, just the same in the mirror as in real life. But if observed closely, some details are different. The ball in the player’s right hand now appears in their left hand in the mirror. While the mirror image still shows the same hand, it has clearly changed from a left to a right hand or vice versa. Many other physical objects also have mirror images that differ in a key aspect, just like hands, which is why scientists call them handed or chiral (from Greek χϵρι = hand). Others, like the ball, cannot be distinguished from their mirror image, which makes them achiral.

Chirality is one of the most fundamental geometric properties and plays a special role in biology, chemistry and physics. It can cause surprising effects: One version of the carvone molecule, for example, produces a spearmint smell but its chiral—mirrored—equivalent smells of caraway.

The best examples are simple. This is especially true in quantum computing, where complexity can get out of hand pretty fast. A team of researchers at D-Wave, with collaborators from USC, Tokyo Tech, and Saitama Medical University, recently explored a quantum phase transition — a complex subject by anyone’s standards — in a very simple 1D chain of magnetic spins. Our work, published today in Nature Physics, studies quantum critical dynamics in a coherently annealed Ising chain. Here are a few things we learned along the way.

Programmable quantum phase transitions, as ordered

Phase transitions, such as water to ice, are commonly attributed to changes in temperature. But there is another type of phase transition —-a quantum phase transition (QPT) —-where quantum effects determine the properties of a physical system, in the absence of thermal effects. In a 1D chain, spins at the end of the simulation are either “up” or “down”, and we get “kinks” separating blocks of up spins and down spins (during the simulation, spins can be in a superposition of up and down). The density and spacing of kinks depend on, among other things, the speed and “quantumness” of the experiment. In this work we guided the programmable system of spins through a QPT and investigated the effect of varying parameters such as speed, system size, and temperature.

Scientists have demonstrated a powerful technique that will allow quantum computers to store much more information in photons of light. The team managed to encode eight levels of data into photons and read it back easily, representing an exponential leap over previous systems.

Traditional computers store and process information in binary bits, which can hold a value of zero or one. Quantum computers boost this power drastically with their quantum bits, or qubits, which can hold values of zero, one or both at the same time. But an emerging version of qubits, known as qudits, up the game even more. Rather than just two values like qubits, qudits can theoretically contain dozens of different values, greatly increasing the data processing and storage potential. Better yet, qudits are also more resilient against external noise that can disrupt qubits.

But, of course, there’s a catch: it’s hard to measure and read back data stored on qudits. So for the new study, researchers at Oak Ridge National Laboratory, Purdue University and EPFL have developed a technique to produce and read qudits more reliably. In their experiments, they generated qudits that could each hold up to eight levels of information, and quantum-entangled them in pairs to generate a 64-dimensional quantum space. This, the team says, is four times larger than in previous studies.