Lifeboat Foundation

GPS for scuba divers, cars with built-in holographic maps, and other new tech mean ’you’ll never get lost again.‘.

Linking acoustic and seismic signals from meteorite strikes to orbiter images is a step toward mapping the planet’s interior.

Light-pulse matter-wave interferometers exploit the quantized momentum kick given to atoms during absorption and emission of light to split atomic wave packets so that they traverse distinct spatial paths at the same time. Additional momentum kicks then return the atoms to the same point in space to interfere the two matter-wave wave packets. The key to the precision of these devices is the encoding of information in the phase ϕ that appears in the superposition of the two quantum trajectories within the interferometer. This phase must be estimated from quantum measurements to extract the desired information. For N atoms, the phase estimation is fundamentally limited by the independent quantum collapse of each atom to an r.m.s. angular uncertainty \(\Delta {\theta }_{{\rm{SQL}}}=1/\sqrt{N}\) rad, known as the standard quantum limit (SQL)².

Here we demonstrate a matter-wave interferometer^31,32 with a directly observed interferometric phase noise below the SQL, a result that combines two of the most striking features of quantum mechanics: the concept that a particle can appear to be in two places at once and entanglement between distinct particles. This work is also a harbinger of future quantum many-body simulations with cavities^26,27,28,29 that will explore beyond mean-field physics by directly modifying and probing quantum fluctuations or in which the quantum measurement process induces a phase transition³⁰.

Quantum entanglement between the atoms allows the atoms to conspire together to reduce their total quantum noise relative to their total signal^1,3. Such entanglement has been generated between atoms using direct collisional^{33,34,35,36,37,38,39} or Coulomb^40,41 interactions, including relative atom number squeezing between matter waves in spatially separated traps^33,35,39 and mapping of internal entanglement onto the relative atom number in different momentum states⁴². A trapped matter-wave interferometer with relative number squeezing was realized in ref. ³⁵, but the interferometer’s phase was antisqueezed and thus the phase resolution was above the SQL.

Pictures of the sky can show us cosmic wonders; movies can bring them to life. Movies from NASA’s NEOWISE space telescope are revealing motion and change across the sky.

Every six months, NASA’s Near-Earth Object Wide Field Infrared Survey Explorer, or NEOWISE, spacecraft completes one trip halfway around the Sun, taking images in all directions. Stitched together, those images form an “all-sky” map showing the location and brightness of hundreds of millions of objects. Using 18 all-sky maps produced by the spacecraft (with the 19th and 20th to be released in March 2023), scientists have created what is essentially a time-lapse movie of the sky, revealing changes that span a decade.

Continue reading “NASA telescope takes 12-year time-lapse movie of entire sky” »

The spatiotemporal analysis of brain activation during syllogistic reasoning, and the execution of 1 baseline task (BST) were performed in 14 healthy adult participants using high-density event-related brain potentials (ERPs). The following results were obtained: First, the valid syllogistic reasoning task (VSR) elicited a greater positive ERP deflection than the invalid syllogistic reasoning task (ISR) and BST between 300 and 400 ms after the onset of the minor premise. Dipole source analysis of the difference waves (VSR-BST and VSR-ISR) indicated that the positive components were localized in the vicinity of the occipito-temporal cortex, possibly related to visual premise processing. Second, VSR and ISR demonstrated greater negativity than BST developed at 600–700 ms. Dipole source analysis of difference waves (VSR-BST and ISR-BST) indicated that the negative components were mainly localized near the medial frontal cortex/the anterior cingulate cortex, possibly related to the manipulation and integration of premise information. Third, both VSR and ISR elicited a more positive ERP deflection than BST between 2,500 and 3,000 ms. Voltage maps of the difference waves (VSR-BST and VSR-ISR) demonstrated strong activity in the right frontal scalp regions. Results indicate that the reasoning tasks may require more mental effort to spatial processing of working memory.

A study led by researchers from the Institute Cajal of Spanish Research Council (CSIC) in Madrid, Spain in collaboration with the Bioengineering Department of George Mason University in Virginia, U.S. has updated one of the world’s largest databases on neuronal types, Hippocampome.org.

The study, which is published in the journal PLOS Biology, represents the most comprehensive mapping performed to date between neural activity recoded in vivo and identified neuron types. This major breakthrough may enable biologically meaningful computer modeling of the full neuronal circuit of the hippocampus, a region of the brain involved in memory function.

Circuits of the mammalian cerebral cortex are made up of two types of neurons: Excitatory neurons, which release a neurotransmitter called glutamate, and inhibitory neurons, which release GABA (gamma-aminobutanoic acid), the main inhibitor of the central nervous system. “A balanced dialogue between the ‘excitatory’ and ‘inhibitory’ activities is critical for brain function. Identifying the contribution from the several types of excitatory and inhibitory cells is essential to better understand brain operation,” explains Liset Menendez de la Prida, the Director of the Laboratorio de Circuitos Neuronales at the Institute Cajal who leads the study at the CSIC.

Deep generative models are a popular data generation strategy used to generate high-quality samples in pictures, text, and audio and improve semi-supervised learning, domain generalization, and imitation learning. Current deep generative models, however, have shortcomings such as unstable training objectives (GANs) and low sample quality (VAEs, normalizing flows). Although recent developments in diffusion and scored-based models attain equivalent sample quality to GANs without adversarial training, the stochastic sampling procedure in these models is sluggish. New strategies for securing the training of CNN-based or ViT-based GAN models are presented.

They suggest backward ODEsamplers (normalizing flow) accelerate the sampling process. However, these approaches have yet to outperform their SDE equivalents. We introduce a novel “Poisson flow” generative model (PFGM) that takes advantage of a surprising physics fact that extends to N dimensions. They interpret N-dimensional data items x (say, pictures) as positive electric charges in the z = 0 plane of an N+1-dimensional environment filled with a viscous liquid like honey. As shown in the figure below, motion in a viscous fluid converts any planar charge distribution into a uniform angular distribution.

A positive charge with z 0 will be repelled by the other charges and will proceed in the opposite direction, ultimately reaching an imaginary globe of radius r. They demonstrate that, in the r limit, if the initial charge distribution is released slightly above z = 0, this rule of motion will provide a uniform distribution for their hemisphere crossings. They reverse the forward process by generating a uniform distribution of negative charges on the hemisphere, then tracking their path back to the z = 0 planes, where they will be dispersed as the data distribution.

A whole monkey brain is imaged at high resolution in 100 hours.

A new field of science has been emerging at the intersection of neuroscience and high-performance computing — this is the takeaway from the 2022 BrainComp conference, which took place in Cetraro, Italy from the 19th to the 22nd of September. The meeting, which featured international experts in brain mapping, machine learning, simulation, research infrastructures, neuro-derived hardware, neuroethics and more, strengthened the current collaborations in this emerging field and forged new ones.

Now in its 5th edition, BrainComp first started in 2013 and is jointly organised by the Human Brain Project and the EBRAINS digital research infrastructure, University of Calabria in Italy, the Heinrich Heine University of Düsseldorf and the Forschungszentrum Jülich in Germany. It is attended by researchers from inside and outside the Human Brain Project. This year was dedicated to the computational challenges of brain connectivity. The brain is the most complex system in the observable universe due to the tight connections between areas down to the wiring of the individual neurons: decoding this complexity through neuroscientific and computing advances benefits both fields.

Hosted by the organising committee of Katrin Amunts, Scientific Research Director of the HBP, Thomas Lippert, Leader of EBRAINS Computing Services from the Juelich Supercomputing Centre and Lucio Grandinetti from the University of Calabria, the sessions included a variety of topics over four days.