Category Archives: Quantum Physics
Quantum mechanics tries to explain the reason for the disappearance of black holes – Yourweather.co.uk
Quantum mechanics could explain primordial black holes. Roberta Duarte Meteored Brazil 07/06/2024 07:00 5 min
When we think of black holes, we immediately think of objects larger than the solar system. These are the famous supermassive black holes found at the center of each galaxy. However, the black holes that have been observed have different sizes, ranging from the size of planets to sizes larger than planetary systems.
Since the last century, physicists have theorised about the possibility of the existence of black holes called primordial black holes. These objects would have been generated in the early moments of the universe due to density perturbations in the space-time fabric. Primordial black holes could come in different sizes, from larger than the solar system to the size of an atom.
To date, no primordial black hole has been observed despite increasing efforts in the search for black holes. They have earned the nickname disappearing black holes. A group of physicists proposed a new explanation using Quantum Mechanics for the reason for this disappearance.
One of the most accepted models within Cosmology is the CDM, which is the model in charge of describing the Big Bang. According to this model, the universe is expanding and at some point in the past condensed into a single point. When this point began to expand it was called the Big Bang.
Inflation is the name of one of the first phases of the universe where the first acceleration occurred where the universe rapidly expanded from the size of a lemon to that of a galaxy.
A few moments after the Big Bang, a process called inflation occurred where the universe expanded rapidly. During this moment, the disturbances that existed in the fabric of space-time were also amplified due to the expansion. One possible explanation is that these amplified perturbations allowed for more complex structures hundreds of millions of years later.
One of the consequences of this inflation is the appearance of primordial black holes. They would be black holes that were created precisely when inflation occurred and regions with density differences collapsed. Physicist Stephen Hawking estimated that some of these primordial black holes would reach the end of their lives in the last billion years of the universe.
One hypothesis is that primordial black holes are responsible for at least some of the calculated dark matter. Because they could be isolated and difficult to observe, they would be perceived gravitationally but not through electromagnetic radiation like dark matter. But the mystery still remains as to why we didn't see any specimens.
One of the areas of Physics is Quantum Field Theory (QFT), which combines concepts from quantum mechanics and the theory of relativity. The idea is to describe the particles and interactions present within the Standard Model. Within TQC, particles are described as field excitations found at every point in space.
One of the challenges of TQC is to combine general relativity with the rest of the description within the area. Dark matter also doesn't fit the TQC description well. However, recent work argues that by using TQC tools it is possible to explain why primordial black holes disappear.
One explanation is that during the early universe and inflation, waves had high amplitudes but short wavelengths. The shorter the wavelength, the more energetic the wave. These waves would be associated with the generation of primordial black holes in these early moments.
What the study found is that when looking at the earliest moments of the universe and these waves, known as CMBs, only a few wavelengths are observed. This would explain why we observed few primordial black holes even in CMB observations. These wavelengths associated with primordial black holes would be unrelated.
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Two real-world tests of quantum memories bring a quantum internet closer to reality – Science News Magazine
In the quest to build a quantum internet, scientists are putting their memories to the test. Quantum memories, that is.
Quantum memories are devices that store fragile information in the realm of the very small. Theyre an essential component for scientists vision of quantum networks that could allownew types of communication, from ultra-secure messaging to linking up far-flung quantum computers (SN: 6/28/23). Such memories would help scientistsestablish quantum connections, or entanglement, throughout a network (SN: 2/12/20).
Now, two teams of scientists have entangled quantum memories in networks nestled into cities, where the hustle and bustle of urban life can pose challenges to quantum communications.
These two impressive studies are pushing out of the lab and into real-world implementations, says physicist Benjamin Sussman of the University of Ottawa, who was not involved with the research. These are not just toy systems, but are really the first steps toward what future networks will look like.
In a network of two quantum memories connected by a telecommunications fiber link that traversed a 35-kilometer loop through Boston and Cambridge, Mass., scientistsmaintained entanglement for about a second, physicist Can Knaut and colleagues report in the May 16Nature. That doesnt sound like a lot for us, but in the domain of quantum, where everything is more fleeting, one second is actually a really long time, says Knaut, of Harvard University.
The researchers used quantum memories built from a tiny hunk of diamond in which two of the diamonds normal carbon atoms are replaced by one atom of silicon. That substitution creates a defect that serves as a quantum bit, or qubit. In fact, the defect serves as two qubits one thats short-lived, and another long-lived qubit that acts as the memory. Scientists prodded the short-lived qubit with a photon, or particle of light. The researchers used that qubit as a go-between in order to entangle the long-lived qubit with the photon. Then the scientists sent the photon through the fiber and repeated the process to entangle the long-lived qubits in each memory.
Meanwhile, in Hefei, China, entanglement was achieved in a network withthree quantum memoriesseparated by fiber links of about 20 kilometers, researchers report in the same issue ofNature.
This teams quantum memory was based on a large ensemble of rubidium atoms about 1 millimeter in diameter. When hit with a laser, the ensemble of atoms can emit a photon. Rather than shuttling the photon directly to another quantum memory, the photon was sent to a centrally located station, where it was measured along with a photon sent from another memory. That generated entanglement between the two distant parts of the network.
Meeting up in the middle meant the photons didnt have to travel all the way to the other side of the network, an added bonus. This scheme is rather efficient, but its experimental realization is rather challenging, says experimental physicist Xiao-Hui Bao of theUniversity of Science & Technology of China in Hefei. The technique required the team to find methods to correct for changes in the length of the fibers due to temperature shifts and other effects that could cause problems. This painstaking effort is called phase stabilization. This is the main technology advance we made in this paper, Bao says.
In contrast, the Boston network had no central station and didnt require phase stabilization. But both teams achieved whats called heralded entanglement. That means that a signal is sent to confirm that the entanglement was established, which demands that the entanglement persists long enough for information to make its way across the network. That confirmation is important for using such networks for practical applications, says physicist Wolfgang Tittel, who was not involved with either study.
If you compare how these two different groups have achieved [heralded entanglement], you see that there are more differences than similarities, and I find that great, says Tittel, of the University of Geneva. There are different approaches which are all still very, very promising.
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Non-trivial quantum geometry and the strength of electronphonon coupling – Nature.com
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Non-trivial quantum geometry and the strength of electronphonon coupling - Nature.com
Quantum Mechanics Bolsters Drug Discovery with QUELO-G and CUDA Graphs – Blockchain News
Quantum Mechanics Revolutionizing Drug Discovery
According to a blog post on NVIDIA's developer platform, drug discovery is being enhanced through the implementation of quantum mechanics. Traditional approaches to drug discovery have primarily relied on the classical force field, which has proven useful but is widely recognized as lacking in some essential physics. This is where quantum mechanics comes in.
Quantum mechanics introduces a level of complexity to the drug discovery process that classical methods are unable to match. It takes into account the behavior of particles at the quantum level, enabling a more profound understanding of molecular structures and interactions.
The application of quantum mechanics in drug discovery is made possible through the use of QUELO-G and CUDA graphs. QUELO-G is a quantum mechanics-enhanced machine learning algorithm that interacts with CUDA graphs, a powerful tool that facilitates parallel computing. This interaction allows for the simulation of complex molecular structures and reactions, providing invaluable information for the drug discovery process.
NVIDIA, a tech giant renowned for its advances in artificial intelligence and graphics processing units (GPUs), is at the forefront of this quantum leap in drug discovery. The use of their CUDA graphs demonstrates the companys dedication to pushing the boundaries of technological innovation in various fields, including healthcare.
Quantum mechanics is steadily revolutionizing the drug discovery process, with QUELO-G and CUDA graphs leading the charge. As advancements continue, it is expected that these technologies will enable more precise, efficient, and effective drug discovery, potentially leading to breakthrough treatments for a variety of health conditions.
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Quantum Mechanics Bolsters Drug Discovery with QUELO-G and CUDA Graphs - Blockchain News
Quantum to cosmos: Why scale is vital to our understanding of reality – New Scientist
It can be hard to wrap our minds round the very large and the very small. Ron Koeberer/Millennium Images, UK
Imagine setting off on a spacecraft that can travel at the speed of light. You wont get far. Even making it to the other side of the Milky Way would take 100,000 years. It is another 2.5 million years to Andromeda, our nearest galactic neighbour. And there are some 2 trillion galaxies beyond that.
The vastness of the cosmos defies comprehension. And yet, at the fundamental level, it is made of tiny particles.It is a bit of a foreign country both the small and the very big, says particle physicist Alan Barr at the University of Oxford. I dont think you ever really understand it, you just get used to it.
Still, you need to have some grasp of scale to have any chance of appreciating how reality works.
Lets start big, with the cosmic microwave background (CMB), the radiation released 380,000 years after the big bang. The biggest scales weve measured are features in the CMB, says astrophysicist Pedro Ferreira, also at the University of Oxford. These helped us put the diameter of the observable universe at 93 billion light years.
At the other end of the scale, the smallest entities are fundamental particles like quarks. Yet quantum physics paints these as dimensionless blips in a quantum field, with no size at all. So what is the shortest possible distance?
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Quantum to cosmos: Why scale is vital to our understanding of reality - New Scientist
Helping qubits stay in sync – Newswise
Newswise As part of theCenter for Quantum Leaps, a signature initiative of the Arts & Sciences strategic plan, physicistKater Murchand his research group use nano-fabrication techniques toconstruct superconducting quantum circuitsthat allow them to probe fundamental questions in quantum mechanics. Qubits are promising systems for realizing quantum schemes for computation, simulation and data encryption.
Murch and his collaborators published a new paper inPhysical Review Lettersthat explores the effects of memory in quantum systems and ultimately offers a novel solution to decoherence, one of the primary problems facing quantum technologies.
Our work shows that theres a new way to prevent decoherence from corrupting quantum entanglement, said Murch, the Charles M. Hohenberg Professor of Physics at Washington University in St. Louis. We can use dissipation to prevent entanglement from leaving our qubits in the first place.
View the teams illustrated video about their research findings:https://youtu.be/EbeNagXqJEk
Learn more about WashUs quantum research in theAmpersandmagazine.
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How quantum entanglement really works and why we accept its weirdness – New Scientist
Entanglement is a key part ofquantum computing
Bartlomiej K. Wroblewski/Alamy
While scientists generally try to find sensible explanations for weird phenomena, quantum entanglement has them tied in knots.
This link between subatomic particles, in which they appear to instantly influence one another no matter how far apart, defies our understanding of space and time. It famously confounded Albert Einstein, who dubbed it spooky action at a distance. And it continues to be a source of mystery today. These quantum correlations seem to appear somehow from outside space-time, in the sense that there is no story in space and time that explains them, says Nicolas Gisin at the University of Geneva, Switzerland.
But the truth is that, as physicists have come to accept the mysterious nature of entanglement and are using it to develop new technologies, they are doubtful that it has anything left to tell us about how the universe works.
You can create quantum entanglement between particles by bringing them close together so that they interact and their properties become intertwined. Alternatively, entangled particles can be created together in a process such as photon emission or the spontaneous breakup of a single particle such as a Higgs boson.
The spooky thing is that, in the right conditions, if you then send these particles to opposite sides of the universe, performing a measurement on one will instantaneously affect the outcome of a measurement on the other, despite the fact that there can be no information exchanged between them.
For Einstein,
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How quantum entanglement really works and why we accept its weirdness - New Scientist
The Quantum Twist: Unveiling the Proton’s Hidden Spin – SciTechDaily
Researchers have developed a new method that merges experimental data with advanced calculations to explore how gluons contribute to proton spin, revealing complex dynamics and setting the stage for future three-dimensional proton imaging. Credit: SciTechDaily.com
New research combining experimental and computational approaches provides deeper insights into proton spin contributions from gluons.
Nuclear physicists have been tirelessly exploring the origins of proton spin. A novel approach, merging experimental data with cutting-edge calculations, has now illuminated the spin contributions from gluonsthe particles that bind protons. This advancement also sets the stage for three-dimensional imaging of the proton structure.
Joseph Karpie, a postdoctoral associate at the Center for Theoretical and Computational Physics (Theory Center) at the U.S. Department of Energys Thomas Jefferson National Accelerator Facility, led this groundbreaking research.
He said that this decades-old mystery began with measurements of the sources of the protons spin in 1987. Physicists originally thought that the protons building blocks, its quarks, would be the main source of the protons spin. But thats not what they found. It turned out that the protons quarks only provide about 30% of the protons total measured spin. The rest comes from two other sources that have so far proven more difficult to measure.
One is the mysterious but powerful strong force. The strong force is one of the four fundamental forces in the universe. Its what glues quarks together to make up other subatomic particles, such as protons or neutrons. Manifestations of this strong force are called gluons, which are thought to contribute to the protons spin. The last bit of spin is thought to come from the movements of the protons quarks and gluons.
A global analysis of experimental data and lattice Quantum Chromodynamics calculations provides insight into the role of the gluons (purple squiggles) contributing to the spin of the nucleon. Credit: Jefferson Lab
This paper is sort of a bringing together of two groups in the Theory Center who have been working toward trying to understand the same bit of physics, which is how do the gluons that are inside of it contribute to how much the proton is spinning around, he said.
He said this study was inspired by a puzzling result that came from initial experimental measurements of the gluons spin. The measurements were made at the Relativistic Heavy Ion Collider, a DOE Office of Science user facility based at Brookhaven National Laboratory in New York. The data at first seemed to indicate that the gluons may be contributing to the protons spin. They showed a positive result.
But as the data analysis was improved, a further possibility appeared.
When they improved their analysis, they started to get two sets of results that seemed quite different, one was positive and the other was negative, Karpie explained.
While the earlier positive result indicated that the gluons spins are aligned with that of the proton, the improved analysis allowed for the possibility that the gluons spins have an overall negative contribution. In that case, more of the proton spin would come from the movement of the quarks and gluons, or from the spin of the quarks themselves.
This puzzling result was published by the Jefferson Lab Angular Momentum (JAM) collaboration.
Meanwhile, the HadStruc collaboration had been addressing the same measurements in a different way. They were using supercomputers to calculate the underlying theory that describes the interactions among quarks and gluons in the proton, Quantum Chromodynamics (QCD).
To equip supercomputers to make this intense calculation, theorists somewhat simplify some aspects of the theory. This somewhat simplified version for computers is called lattice QCD.
Karpie led the work to bring together the data from both groups. He started with the combined data from experiments taken in facilities around the world. He then added the results from the lattice QCD calculation into his analysis.
This is putting everything together that we know about quark and gluon spin and how gluons contribute to the spin of the proton in one dimension, said David Richards, a Jefferson Lab senior staff scientist who worked on the study.
When we did, we saw that the negative things didnt go away, but they changed dramatically. That meant that theres something funny going on with those, Karpie said.
Karpie is lead author on the study that was recently published in Physical Review D. He said the main takeaway is that combining the data from both approaches provided a more informed result.
Were combining both of our datasets together and getting a better result out than either of us could get independently. Its really showing that we learn a lot more by combining lattice QCD and experiment together in one problem analysis, said Karpie. This is the first step, and we hope to keep doing this with more and more observables as well as we make more lattice data.
The next step is to further improve the datasets. As more powerful experiments provide more detailed information on the proton, these data begin painting a picture that goes beyond one dimension. And as theorists learn how to improve their calculations on ever-more powerful supercomputers, their solutions also become more precise and inclusive.
The goal is to eventually produce a three-dimensional understanding of the protons structure.
So, we learn our tools do work on the simpler one-dimension scenario. By testing our methods now, we hopefully will know what we need to do when we want to move up to do 3D structure, Richards said. This work will contribute to this 3D image of what a proton should look like. So its all about building our way up to the heart of the problem by doing this easier stuff now.
Reference: Gluon helicity from global analysis of experimental data and lattice QCD Ioffe time distributions by Jefferson Lab Angular Momentum and HadStruc Collaborations, J. Karpie, R. M. Whitehill, W. Melnitchouk, C. Monahan, K. Orginos, J.-W. Qiu, D. G. Richards, N. Sato and S. Zafeiropoulos, 27 February 2024,Physical Review D. DOI: 10.1103/PhysRevD.109.036031
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The Quantum Twist: Unveiling the Proton's Hidden Spin - SciTechDaily
Bruce Gordon: Idealism, Quantum Mechanics, and the Fundamentality of Mind – Walter Bradley Center for Natural and Artificial Intelligence
Michael Egnor May 23, 2024 1 Michael Egnor May 23, 2024 1
Does quantum mechanics, properly understood, point to the fundamentality of mind in the universe? In this episode, Michael Egnor concludes a conversation with philosopher of physics Bruce Gordon about the relationship between idealism and quantum mechanics. Gordon argues that quantum mechanics points to mind as the fundamental unit of the universe, as it is irreducibly probabilistic and exhibits non-local phenomena. He dismisses interpretations such as Bohmian mechanics and Everett’s many-worlds hypothesis as flawed and suggests that a theistic metaphysic can provide a coherent explanation for the probabilistic nature of quantum mechanics. Gordon also discusses the compatibility of free will with determinism and the nature of God’s freedom. Finally, he challenges the notion of the existence of electrons as physical entities and suggests that they do not exist in our experiential reality. Tune in for the conclusion to a fascinating conversation!
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Quantum Leap: Atom Interference and a Breakthrough in Boson Sampling – SciTechDaily
La Nia Sea Surface Height, December 1, 2021
This coupling of the atmosphere and ocean alters atmospheric circulation and jet streams in ways that intensify rainfall in some regions and bring drought to others.
For the second year in a row, the cooler sister to El Nio showed up at the winter party in the Eastern Pacific. La Nia is expected to stick around until at least spring 2022 in the Northern Hemisphere.
Part of the El Nio-Southern Oscillation cycle, La Nia appears when energized easterly trade winds intensify the upwelling of cooler water from the depths of the eastern tropical Pacific, causing a large-scale cooling of the eastern and central Pacific ocean surface near the Equator. These stronger than usual trade winds also push the warm equatorial surface waters westward toward Asia and Australia. This dramatic cooling of the oceans surface layers then affects the atmosphere by modifying the moisture content across the Pacific. This La Nia coupling of the atmosphere and ocean alters global atmospheric circulation and can cause shifts in the path of mid-latitude jet streams in ways that intensify rainfall in some regions and bring drought to others.
In the western Pacific, rainfall can increase dramatically over Indonesia and Australia during La Nia. Clouds and rainfall become more sporadic over the central and eastern Pacific Ocean, which can lead to dry conditions in Brazil, Argentina, and other parts of South America and wetter conditions over Central America. In North America, cooler and stormier conditions often set in across the Pacific Northwest, while weather typically becomes warmer and drier across the southern United States and northern Mexico. (These and other trends are reflected in the map lower in this story.)
The image above shows conditions across the central and eastern Pacific Ocean as observed from November 26 to December 5, 2021, by the Sentinel-6 Michael Freilich satellite and analyzed by scientists at NASAs Jet Propulsion Laboratory (JPL). The globe depicts sea surface height anomalies. Shades of blue indicate sea levels that were lower than average; normal sea-level conditions appear white; and reds indicate areas where the ocean stood higher than normal. The expansion and contraction of the ocean surface is a good proxy for temperatures because warmer water expands to fill more volume, while cooler water contracts.
This moderate strength La Nia can be seen in the Sentinel-6 data as an area of lower-than-normal sea level along and below the Equator in the central and eastern Pacific, said Josh Willis, a climate scientist and oceanographer at JPL. He noted that the deep trough (blue) above the Equator is not the La Nia water mass; it is a shift in the North Equatorial Counter Current, which tends to strengthen during La Nia events.
December 1, 2021
This La Nia probably means bad news for the American Southwest, which should see lower than normal rainfall this winter, Willis said. This La Nia may not be a whopper, but its still an unwelcome sign for an area already deep into a drought.
The La Nia event that started in late 2020 fits into a larger climate pattern that has been going on for nearly two decadesa cool (negative) phase of the Pacific Decadal Oscillation (PDO). During most of the 1980s and 1990s, the Pacific was locked in a PDO warm phase, which coincided with several strong El Nio events. But since 1999, a cool phase has dominated. The long-term drought in the American Southwest coincides with this trend, Willis noted.
In a report released on December 9, 2021, the NOAA Climate Prediction Center noted that sea surface temperatures in November in the eastern tropical Pacific ranged from 0.7 to 1.2 degrees Celsius (1.26 to 2.16 degrees Fahrenheit) below the long-term average and 0.9C (1.62F) below average in the Nio 3.4 region of the tropical Pacific (from 170 to 120 West longitude). Forecasters predicted La Nia conditions would persist through Northern Hemisphere winter, with a 60 percent chance that the ocean would transition back to neutral conditions during the April through June period.
This La Nia is the first to be observed by Sentinel-6 Michael Freilich, which was launched in November 2020. The new satellite is giving us a great picture of this La Nia, Willis said. With the public release of the missions climate-quality data, we are now in a position where Sentinel-6 Michael Freilich can soon take over the climate record of sea level rise, which goes all the way back to the early 1990s.
Engineers and scientists have spent the past year calibrating and analyzing data from the new satellite against the existing Jason-3 mission. The team is ensuring that the new, more advanced data correlate properly with long-term records. New, high-resolution Sentinel-6 Michael Freilich data sets were released at the end of November 2020.
NASA Earth Observatory images by Joshua Stevens, using modified Copernicus Sentinel data (2021) processed by the European Space Agency courtesy of Josh Willis/NASA/JPL-Caltech, and information adapted from the Famine Early Warning Systems Network.
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