Researchers at the Humboldt University of Berlin, partners of the DAALI project, have demonstrated a surprising effect present in the fluorescent light of a single atom.
An atom is the smallest component of an element. It is made up of protons and neutrons within the nucleus, and electrons circling the nucleus.
The incoherent component of the fluorescence from a single two-level atom is investigated after rejecting the coherent component. Contrary to intuition, its photon statistics experimentally shows strong photon bunching. This result suggests that the atom does in fact simultaneously scatter two photons.
A German-French research team led by Bayreuth microbiologist Dirk Schüler presents new findings on the functionality of proteins in magnetic bacteria in the journal mBio. The research is based on previous results published recently in the same journal.
In this study, the Bayreuth scientists used bacteria of the species Magnetospirillum gryphiswaldense to decipher the function of genes that are presumably involved in the biosynthesis of magnetosomes in other magnetic bacteria that are difficult to access.
Magnetic bacteria contain magnetic particles consisting of nanocrystals of an iron mineral inside their cells. These organelle-like particles are known in research as magnetosomes. Like links in a chain, well over 20 of these particles are regularly lined up one after the other. The magnetic moments of the individual crystals add up so that the chain—similar to a compass needle—has the function of a magnetic sensor: It aligns the bacterial cell in the relatively weak magnetic field of the Earth.
California-based startup Atom Computing has announced a 1,225-qubit quantum computer, the first to break the 1,000+ barrier, which it plans to release in 2024.
Quantum bits, or qubits, are the basic units of information in quantum computing – equivalent to bits in classical computing. Unlike bits, however, qubits can exist in multiple states simultaneously, allowing them to perform calculations that would take millions of years for an ordinary computer.
A quantum computing platform that is capable of the simultaneous operation of multiple spin-based quantum bits (qubits) has been created by researchers in South Korea. Designed by Yujeong Bae, Soo-hyon Phark, Andreas Heinrich and colleagues at the Institute for Basic Science in Seoul, the system is assembled atom-by-atom using a scanning tunnelling microscope (STM).
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While quantum computers of the future should be able to outperform conventional computers at certain tasks, today’s nascent quantum processors are still too small and noisy to do practical calculations. Much more must be done to create viable qubit platforms that can retain information for long enough for quantum computers to be viable.
A highly unstable nucleus that decays by emitting five protons has been observed, offering an extreme case for testing nuclear models.
Researchers have found evidence of an extremely unstable nucleus for which more than half of the component particles are unbound, meaning that they are not tightly connected to the dense core of the nucleus [1]. The nucleus, nitrogen-9, is composed of a small helium-like core surrounded by five untethered protons that quickly escape after the nucleus’s formation. Previous experiments have seen at most four unbound protons in a nucleus. The research team had to carefully sift through a large volume of nuclear-collision data to identify the nitrogen-9 decays. This barely bound nucleus poses a unique challenge to theories of nuclear structure.
A nucleus with a large imbalance between its numbers of protons and neutrons is less stable than one in which the numbers are similar. In the extreme cases, these proton-or neutron-rich isotopes are unbound, meaning that one or more nucleons escape during decay. The boundaries between bound and unbound states—both on the proton-rich and on the neutron-rich sides of the nuclear landscape—are called drip lines. Researchers are interested in finding nuclei beyond the drip lines because they offer tests of models at the limits of nuclear existence. These exotic nuclei may also play a role in the formation of heavy elements in supernovae and in neutron star mergers.
A new study published in Nature Communications delves into the manipulation of atomic-scale spin transitions using an external voltage, shedding light on the practical implementation of spin control at the nanoscale for quantum computing applications.
Spin transitions at the atomic scale involve changes in the orientation of an atom’s intrinsic angular momentum or spin. In the atomic context, spin transitions are typically associated with electron behavior.
In this study, the researchers focused on using electric fields to control the spin transitions. The foundation of their research was serendipitous and driven by curiosity.
In a new collaboration, two research groups, one led by Francesca Ferlaino and one by Markus Greiner, have joined force to develop an advanced quantum gas microscope for magnetic quantum matter. This state-of-the-art instrument reveals intricate dipolar quantum phases shaped by the interactions as reported in Nature.
Magnetic atoms are central to Ferlaino’s research on unexplored quantum matter. At both the Institute of Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences and the Department of Experimental Physics at the University of Innsbruck, the experimental physicist and her team achieved the first Bose-Einstein condensate of erbium in 2012. In 2019, she led one of the teams observing for the first time supersolid states in ultracold quantum gases of magnetic atoms.
At Harvard University, German experimental physicist Markus Greiner is the pioneer of optical techniques allowing for the direct observation of individual atoms. Using high-resolution microscopy, the Harvard team has unveiled many exotic phenomena in strongly correlated ultracold atoms, as anti-ferromagnetic phases in 2017.
Physicists, building on Lev Landau’s theory of quasiparticles, used ultracold quantum gases to simulate electron behavior in solids. Their recent experiment revealed that these quasiparticles can have both attractive and repulsive interactions, underscoring the significance of quantum statistics.
An electron moving through a solid generates a polarization in its environment due to its electric charge. In his theoretical considerations, the Russian physicist Lev Landau extended the description of such particles by their interaction with the environment and spoke of quasiparticles. More than ten years ago, the team led by Rudolf Grimm at the Institute of Quantum Optics and Quantum Information (IQQOI) of the Austrian Academy of Sciences (ÖAW) and the Department of Experimental Physics of the University of Innsbruck succeeded in generating such quasiparticles for both attractive and repulsive interactions with the environment.
For this purpose, the scientists use an ultracold quantum gas consisting of lithium and potassium atoms in a vacuum chamber. With the help of magnetic fields, they control the interactions between the particles, and by means of radio-frequency pulses push the potassium atoms into a state in which they attract or repel the lithium atoms surrounding them. In this way, the researchers simulate a complex state similar to the one produced in the solid state by a free electron.
The scale of quantum computers is growing quickly. In 2022, IBM took the top spot with its 433-qubit Osprey chip. Yesterday, Atom Computing announced they’ve one-upped IBM with a 1,180-qubit neutral atom quantum computer.
The new machine runs on a tiny grid of atoms held in place and manipulated by lasers in a vacuum chamber. The company’s first 100-qubit prototype was a 10-by-10 grid of strontium atoms. The new system is a 35-by-35 grid of ytterbium atoms (shown above). (The machine has space for 1,225 atoms, but Atom has so far run tests with 1,180.)
Quantum computing researchers are working on a range of qubits—the quantum equivalent of bits represented by transistors in traditional computing—including tiny superconducting loops of wire (Google and IBM), trapped ions (IonQ), and photons, among others. But Atom Computing and other companies, like QuEra, believe neutral atoms—that is, atoms with no electric charge—have greater potential to scale.
