Caltech > About > News > “Ultrafast Camera Takes 1 Trillion Frames Per Second of Transparent Objects and Phenomena” (January 17, 2020).

]]>Wang explains that his new imaging system combines the high-speed photography system he previously developed with an old technology, phase-contrast microscopy, that was designed to allow better imaging of objects that are mostly transparent such as cells, which are mostly water.

The fast-imaging portion of the system consists of something Wang calls lossless encoding compressed ultrafast technology (LLE-CUP).

Unlike most other ultrafast video-imaging technologies that take a series of images in succession while repeating the events, the LLE-CUP system takes a single shot, capturing all the motion that occurs during the time that shot takes to complete.Since it is much quicker to take a single shot than multiple shots,LLE-CUP is capable of capturing motion, such as the movement of light itself, that is far too fast to be imaged by more typical camera technology.In the new paper, Wang and his fellow researchers demonstrate the capabilities of pCUP by imaging the spread of a shockwave through water and of a laser pulse traveling through a piece of crystalline material.

Space.com > “Tour the colorful Crab Nebula with this stunning new 3D visualization” by Doris Elin Urrutia (January 15, 2020) – The visualization is from a new generation of products being created by NASA’s Universe of Learning Program, an effort to connect scientific work with lay audiences. **This particular video aims to highlight the reasons behind observing space through different wavelengths.**

]]>A new 3D movie highlights the Crab Nebula, beginning with its location in the constellation Taurus and zooming in to show off its dynamic features.

Data from the Hubble Space Telescope, Spitzer Space Telescope and the Chandra X-ray Observatory … [provide] a fuller understanding of the Crab Nebula’s world.

The video was unveiled Jan. 5 at the 235th meeting of the American Astronomical Society in Honolulu, Hawaii.

[Image caption] The Crab Nebula was once mistaken for a comet by French astronomer Charles Messier. …

YouTube > MasterClass > Promo > “Neil deGrasse Tyson Teaches Scientific Thinking and Communication | Official Trailer | MasterClass” (posted Dec 19, 2019 [Link to class in description below.]

“One of the great challenges in this world is knowing enough about a subject to think you’re right but not enough about the subject to know you’re wrong.”

Neil deGrasse Tyson was just nine years old when he became fascinated by the mysteries of the cosmos. Today he’s known worldwide for inspiring others to consider the world—and the universe—around us. The astrophysicist, director at the world-renowned

Hayden Planetarium in New York City, and science influencer has been a powerful advocate forscience literacywith a popular television series and the NYT–bestselling bookAstrophysics for People in a Hurry. He’s been awarded the U.S. National Academy of Sciences Public Welfare Medal for his “extraordinary role in exciting the public about the wonders of science.” Now he’s teaching you how he connects with audiences around the world.In his MasterClass, Neil deGrasse Tyson teaches you how to discover and communicate

objective truthsin clear, exciting, and engaging ways.Learn to think, measure, and weigh information like a scientist; detect flaws in your own reasoning and navigate cognitive bias; andgauge the credibility of information and ideas. He also teaches you his personal approach to communicating, whether you’re presenting to an audience, delivering a sound bite, or simply conversing with friends and family around the dinner table.In this online class, you’ll learn about:

• Scientific literacy

• Cognitive bias

• Personal and political truths

• The scientific method

• Making predictions

• Scientific measurement

• Effective communication

• Connecting with an audience

• Creating a sound bite

• Inspiring curiosity

[Basically, strengthen what Carl Sagan called your “Baloney Detector.”]

]]>Space.com > “Astronomers just tracked the interstellar journey of one of life’s building blocks through space” by Chelsea Gohd (January 15, 2020).

Scientists have traced the journey of phosphorous, one of the essential building blocks for life as we know it on Earth, through the star-forming regions of space.

Phosphorous, an element present in our DNA and RNA and in cell membranes, is a critical ingredient for life on Earth. But scientists don’t have a clear picture of exactly how the element made its way to our young planet and exactly how life began.

For this study, astronomers used data from the

Atacama Large Millimeter/Submillimeter Array (ALMA), the European Southern Observatory (ESO) and the Rosetta probe[Rosetta Orbiter’s Spectrometer for Ion and Neutral Analysis instrument – ROSINA]from the European Space Agency.The team found that gas from young, massive stars created openings in the star-forming interstellar clouds, and on the walls of those cavities,

phosphorous-bearing moleculesform. Additionally, they found thatphosphorous monoxidewas the most abundant of these types of molecules.… the team studied the comet 67P/Churyomov-Gerasimenko, which the Rosetta probe was sent to observe. They hoped that by following the trail of these phosphorous-bearing molecules from where they originated, they might see how those molecules can get trapped in the

icy dust grainsthat surround a star.

… those icy dust grains … could come together to eventually form comets.[Kathrin Altwegg, the principal investigator for ROSINA and one of the authors of this new study, noted that:] “As comets most probably delivered large amounts of organic compounds to the Earth, the phosphorus monoxide found in comet 67P may strengthen the link between comets and life on Earth.”

**Additional references**

• YouTube > European Southern Observatory (ESO) > “Zooming into star-forming region AFGL 5142” (posted January 15, 2020): This video starts by showing a wide-field view of a region of the sky in the **constellation of Auriga**. It then zooms in to show the **star-forming region AFGL 5142** [~2 kiloparsecs away], recently observed with ALMA.

• eso2001 — Science Release > “Astronomers Reveal Interstellar Thread of One of Life’s Building Blocks – ALMA and Rosetta map the journey of phosphorus” (15 January 2020)

]]>[Image (see image in post above) caption] This Hubble Space Telescope photograph features **spiral galaxy UGC 2885 (Rubin’s galaxy)**, located 232 million light-years away in the northern constellation Perseus. The brightest star in this picture belongs to the Milky Way and is located much closer to Earth than UGC 2885. Image credit: NASA/ESA/B. Holwerda (University of Louisville).

*The arms and core of the Andromeda Galaxy glow among a sea of multicolored stars in this deep-space photo captured from the Cumeada Observatory at the Dark Sky Alqueva Reserve in Reguengos de Monsaraz, Portugal. Image credit: Miguel Claro.*

]]>“How it got so big is something we don’t quite know yet,” [University of Louisville in Kentucky researcher] Holwerda said in the Hubble statement. “It’s as big as you can make a disk galaxy without hitting anything else in space.”

So, entangling 2 photons is one thing, but how do you entangle 100 atoms?

]]>The electrons, photons, and other particles that make up our universe can become inextricably linked, such that the state observed in one particle will be identical for the other. That connection, known as entanglement, remains strong even across vast distances.

“When particles are entangled, it’s as if they are born that way, like twins,” says Xie Chen, associate professor of theoretical physics at Caltech. “Even though they might be separated right after birth, [they’ll] still look the same. And they grow up having a lot of personality traits that are similar to each other.”

“It may be tempting to think that the particles are somehow communicating with each other across these great distances, but that is not the case,” says Thomas Vidick, a professor of computing and mathematical sciences at Caltech. “

There can be correlation without communication.” Instead, he explains, entangled particles are so closely connected thatthere is no need for communication; they “can be thought of as one object.”Or, to simplify, consider two “entangled” quarters, each hidden under a cup. If two people,

BobandAlice, were each to take one of those quarters to a different room, the quarters would remain both heads and tails until one person lifted the cup and observed his or her quarter; at that point, it would randomly become either heads or tails. If Alice were to lift her cup first and her quarter was tails, then when Bob observed his quarter, it would also be tails. If you repeated the experiment and the coins are covered once more, they would go back to being in a state of superposition. Alice would lift her cup again and might find her quarter as heads this time. Bob would then also find his quarter as heads. Whether the first quarter is found to be heads or tails is entirely random.According to Manuel Endres, an assistant professor of physics at Caltech, one of the first steps toward understanding

many-body entanglementis to create and control it in the lab. To do this, Endres and his team use a brute force approach: they design and build laboratory experiments with the goal of creating a system of 100 entangled atoms.Another factor in creating and controlling quantum systems has to do with their delicate nature. Like Mimosa pudica ,a member of the pea family also known as the “sensitive plant,” which droops when its leaves are touched, entangled states can easily disappear, or collapse, when the environment changes even slightly.

The problem is that entangled particles become entangled with the environment around them quickly, in a matter of microseconds or faster. This then destroys the original entangled state a researcher might attempt to study or use.

Even one stray photon flying through an experiment can render the whole thing useless.“

You need to be able to create a system that is entangled only with itself, not with your apparatus,” says Endres. “We want the particles to talk to one another in a controlled fashion. But we don’t want them to talk to anything in the outside world.”“Up until about 20 years ago, the best way to explore entanglement was to look at what nature gave us and try to study the exotic states that emerged,” notes Painter. “Now our goal is to try to synthesize these systems and go beyond what nature has given us.”

While entanglement is the key to advances in quantum-information sciences, it is also a concept of interest to theoretical physicists, some of whom believe that space and time itself are the result of an underlying network of quantum connections.

Quanta Magazine > “The Universal Law That Aims Time’s Arrow” by Natalie Wolchover (August 1, 2019)

]]>But while it’s easy to see where thermalization leads (to tepid coffee and eventual heat death), it’s less obvious how the process begins. “If you start far from equilibrium, like in the early universe, how does the arrow of time emerge, starting from first principles?” said Jürgen Berges, a theoretical physicist at Heidelberg University in Germany who has studied this problem for more than a decade.

… examples [of such systems] include the hottest plasma ever produced on Earth and the coldest gas, and perhaps also the field of energy that theoretically filled the universe in its first split second …In particular, far-from-equilibrium systems exhibit fractal-like behavior, which means they look very much the same at different spatial and temporal scales. … All kinds of quantum systems in various extreme starting conditions seem to fall into this fractal-like pattern, exhibiting universal scaling for a period of time before transitioning to standard thermalization.

When Berges began studying far-from-equilibrium dynamics, he wanted to understand

the extreme conditions at the beginning of the universewhen the particles that now populate the cosmos originated.These conditions would have occurred right after “cosmic inflation” — the explosive expansion of space thought by many cosmologists to have jump-started the Big Bang. Inflation would have blasted away any existing particles, leaving only

the uniform energy of space itself: a perfectly smooth, dense, oscillating field of energy known as a “condensate”[which “decayed into the particles that we observe today”].

Hubble Space Telescope > Hubblecast 126: From Ultraviolet to Infrared: Comparing the Hubble and James Webb Space Telescopes

]]>This Hubblecast explores how the NASA/ESA Hubble Space Telescope’s observations differ

across different wavelengths of the electromagnetic spectrum, and how these observations will be complemented by those of the upcoming NASA/ESA/CSA James Webb Space Telescope.

Here’s Ethan Siegel’s take on estimating the age of the universe. Redshift-distance relation. Hubble constant. Standard candles vs. standard rulers. Cosmic matter-energy composition. And why there’s confidence in the value 13.8 billion years.

“You cannot simply change the age of the Universe by changing the Hubble constant.” You must take the Universe’s composition into account (% normal matter, % dark matter, % dark energy) and use a mathematical model consistent with observations.

… many of the ways we have of measuring one parameter (like the expansion rate) are dependent on our assumptions about what the Universe is made out of.

Seigel’s article contains several images with useful captions.

]]>[Image caption]

Standard candles(L) andstandard rulers(R) are two different techniques astronomers use to measure the expansion of space at various times/distances in the past. Based on how quantities like luminosity or angular size change with distance,we can infer the expansion history of the Universe. Using the candle method is part of thedistance ladder, yielding 73 km/s/Mpc. Using the ruler is part of theearly signal method, yielding 67 km/s/Mpc. NASA / JPL-CALTECH[Image caption]

Measuring back in time and distance (to the left of “today”) can inform how the Universe will evolve and accelerate/decelerate far into the future. We can learn that acceleration turned on about 7.8 billion years ago with the current data, but also learn that themodels of the Universe without dark energy have either Hubble constants that are too low or ages that are too young to match with observations. If dark energy evolves with time, either strengthening or weakening, we will have to revise our present picture. This relationship enables us to determine what’s in the Universe by measuring its expansion history. SAUL PERLMUTTER OF BERKELEY[Image caption]

Four different cosmologies lead to the same fluctuation patterns in the CMB, but an independent cross-check can accurately measure one of these parameters independently, breaking the degeneracy.By measuring a single parameter independently (like H_0), we can better constrain what the Universe we live in has for its fundamental compositional properties.However, even with some significant wiggle-room remaining, the age of the Universe isn’t in doubt. MELCHIORRI, A. & GRIFFITHS, L.M., 2001, NEWAR, 45, 321[Image caption]

There are many possible ways to fit the data that tells us what the Universe is made of and how quickly it’s expanding, but these combinations all have one thing in common: they all lead to a Universe that’s the same age, asa faster-expanding Universe must have more dark energy and less matter, while a slower-expanding Universe requires less dark energy and greater amounts of matter. PLANCK COLLABORATION (MAPS AND GRAPHS), E. SIEGEL (ANNOTATIONS)

Nature.com > Article | Open Access | Published: 27 December 2019 > “Quantum Mechanics can be understood through stochastic optimization on spacetimes” by Jussi Lindgren & Jukka Liukkonen in Scientific Reports volume 9, Article number: 19984 (2019).

SciTechDaily presents the background for the research paper but the paper itself is available elsewhere (as noted above).

Lindgren & Liukkonen’s research is connected to the exploration of quantum foundations (as in Sean Carroll’s latest book); and, in particular, the debate about the ontological status of the wave equation.

SciTechDaily summarizes the story of Lindgren & Liukkonen’s dissatisfaction with certain postulates of quantum mechanics: “… you had to accept they were true without it being shown why.” And how they “devised a new method for expressing the laws of quantum mechanics using stochastic methods, a type of mathematics that deals with random chance and probability.”

The paper, published December 27, 2019, in Scientific Reportsexplores how stochastic methods can be used to derive a variety of equations in quantum mechanics from first principles, as opposed to having to build from ad hoc prior postulates. “The method will be useful for teachers or learners because it gives a better understanding of the reason why something is correct,” said Jukka Liukkonen.

The paper itself defines a fuller context for the research.

Here’s their abstract:

The main contribution of this paper is to explain where the imaginary structure comes from in quantum mechanics. It is shown how the demand of relativistic invariance is key and how the geometric structure of the spacetime together with the demand of linearity are fundamental in understanding the foundations of quantum mechanics. We derive the Stueckelberg covariant wave equation from first principles via a stochastic control scheme. From the Stueckelberg wave equation a Telegrapher’s equation is deduced, from which the classical relativistic and nonrelativistic equations of quantum mechanics can be derived in a straightforward manner. We therefore provide meaningful insight into quantum mechanics by deriving the concepts from a coordinate invariant stochastic optimization problem, instead of just stating postulates.

The paper contains impenetrable mathematics beyond my ken, but the general framework is noteworthy.

Since the inception of Quantum Mechanics (QM), there has been an on-going discussion on the ontology of the theory and its interpretations. In particular, there has been recently an intense debate on the validity of the so-called statistical interpretation of QM, see 1,2.

The ontological problem of QM is manifested especially clearly in the measurement problem. Therefore, understanding the physical meaning of the wave function is paramount. To understand the wave function, one needs to understand the equations of quantum physics.

Lindgren & Liukkonen grabbed my attention by noting the mathematical similarity of the Schrödinger equation to the ordinary diffusion equation, since I tend to explore quantum mechanics from a fluid dynamics perspective.

And they discuss in particular how imaginary time (as in complex algebra) arises in the mathematics.

**Highlights**

This study shows that the imaginary nature of various variables in quantum mechanics is due to the structure of the Minkowski metric.

In terms of future research, perhaps one should try to establish the wave equation in a general curved spacetime and thus generalise the metric into a more general form.

… the results presented in this paper do not therefore support the interpretative thesis given by the PBR theorem, which claims to rule out the statistical interpretation of the quantum state. [1]

… we advocate for a realistic interpretation of quantum mechanics. The model presented in this paper suggests that the test particle is moving under the influence of an external random spacetime force.This random movement of the particle induces the transition probability distribution.

… one could make the conjecture that quantum mechanics or quantum field theory is only a phenomenological theoryand the reason for the statistical nature lies within the stochastic nature of the spacetime itself.… this could mean in essence that the energy sources in the space-time have a random character ie. the stress-energy tensor has a random character, …

According to the stochastic control paradigm presented in this paper, the Born rule for the test particle is related naturally to real part of the minimal expected action.

The spacetime diffusion process takes the route which minimizes the expected action; this is the essence of how (transition) probability is tied to energy minimization.

We firmly base our beliefs on the realistic philosophy of quantum mechanics, where reality exists independently of the observer.This inclination is put forward especially lucidly by Sir Karl Popper.

Notes

[1] See also arXiv.org > quant-ph > arXiv:1811.01107 – “Does the PBR Theorem Rule Out a Statistical Understanding of Quantum Mechanics?” by Anthony Rizzi (Submitted on 2 Nov 2018).

The PBR theorem gives insight into how quantum mechanics describes a physical system. This paper explores PBRs’ general result and shows that it does not disallow the

ensemble interpretation of quantum mechanicsand maintains, as it must, the fundamentally statistical character of quantum mechanics (QM). This is illustrated by drawingan analogy with an ideal gas. An ensemble interpretation of the Schrodinger cat experiment that does not violate the PBR conclusion is also given. The ramifications, limits, and weaknesses of thePBR assumptions, especially in light of lessons learned fromBell’s theorem, are elucidated. It is shown that, if valid, PBRs’ conclusion specifies what type of ensemble interpretations are possible. The PBR conclusion would require a more direct correspondence between the quantum state (e.g., |ψ>) and the reality it describes than might otherwise be expected. A simple terminology is introduced to clarify this greater correspondence.

**Terms**

Markov chain

Transition probability density

Sum over all paths

Relativistic invariance

Minkowski spacetime, Minkowski metric

Four-dimensional diffusion

Metric tensor

Planck scale

Hamiltonian, Lagrangian

Einstein summation

Stueckelberg covariant wave equation

Stochastic control scheme

Dirac equation

Telegrapher’s equation

Born rule

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