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Could an updated Feynman experiment finally lead to a Theory of Everything?
Measuring quantum gravity has proven extremely challenging, stymying some of the greatest minds in physics for generations.
For over a century, the two leading theories in physics have had irreconcilable differences, and scientists have scrambled to find ways to square them, to no avail. An experiment proposed in 1957 by American luminary Richard Feynman, is now getting a makeover, and the results could be significant.
Scientists at Oxford University and University College London (UCL), are attempting to overhaul one of the late Nobel Laureate's experiments and in doing so, hope to heal the rift in a dramatic fashion. Could a Theory of Everything be near? This would be incorporating all four physical forces: gravity, electromagnetism, and the strong and weak nuclear forces, into one solid working theory.
Thus far, theoretical physicist Steven Weinberg, himself a Nobel Laureate, has only been able to combine electromagnetism and the weak nuclear force. A final theory—as Weinberg calls it, would mark the end of physics as we know it. Although the laws of general relativity and quantum mechanics work exceptionally well in their own spheres, some of the rules that govern one area don’t work in the other, and vice-versa. For instance, Relativity explains the gravitational force as it relates to bodies on Earth or in space. But it falls apart on the quantum level.
The merging of two neutron stars. Einstein’s general relativity helps us understand the gravitational forces involved well. Where it gets lost is on the quantum level. Credit: European Space Agency (ESA).
The current upgrade to Feynman’s proposal focuses on quantum gravity. Two papers on the upcoming experiment were published in the journal Physical Review Letters. In the first researchers write, “Understanding gravity in the framework of quantum mechanics is one of the great challenges in modern physics.” A lot of experiments have been proposed, but it’s proven extremely difficult to test quantum gravity in the lab.
One of the reasons, researchers write in the second paper, “Quantum effects in the gravitational field are exceptionally small, unlike those in the electromagnetic field.” Sougato Bose leads the UCL team. He told Physics World, “For example, even the electrostatic force between two electrons overtakes the gravitational force between two kilogram masses by several orders of magnitude.”
These physicists believe if they can detect gravity on the quantum level, it would help us better understand why it operates so differently there, and perhaps reveal the secret to navigating between our two prevailing theories. Feynman’s idea to test for quantum gravity surrounds something known as superposition. A particle is thought to exist in all possible states or positions at once, until measured. Then you can nail down its exact location (or velocity, but not both).
Feynman speculated that using quantum entanglement, one could take a small mass and place it inside a gravitational field, causing it to become entangled with the field on the quantum level. Then, the physicist would be able to detect the field’s interference, before indicating the mass’s position. The interference itself would cause the mass to take a single, specific location or form, which would occur before the mass separated itself from the field. And so in this way, quantum gravity could be detected.
Illustration of a quantum gravity photon race. The purple or high energy photon carries a million times the energy of the yellow one. Yet, it’s thought to move slower as it interacts more with the frothy material of space. In 2009, satellites measured a gamma ray burst from a neutron star collision. Curiously, after traveling approximately 7 billion light years, a pair of such photons arrived just nine-tenths of a second apart. Credit: NASA Goddard Space Flight Center.
Oxford researchers Chiara Marletto and Vlatko Vedral worry that since entanglement isn’t measured directly in Feynman’s proposed experiment, it wouldn’t provide direct evidence of quantum gravity. By quantizing not one but two masses and entangling them, the Oxford physicists say, quantum gravity can be detected directly. Each mass would be in superposition and entangled in a quantum gravity field. UCL physicists added their own element, a “quantum gravity mediator,” to entangle the masses.
To conduct the experiment, two identical interferometers will be placed adjacent to one another. These usually split light up into its constituent parts. But down on the quantum level, these devices interfere with a mass’s quantum wave function, in order to superimpose its quantum state. If gravity is operating on the quantum level, the two masses will become entangled before each leaves its own interferometer.
An artist’s depiction of quantum entanglement. Credit: The National Science Foundation.
Dr. Marletto explained in Physics World,
Our two teams took slightly different approaches to the proposal. Vedral and I provided a general proof of the fact that any system that can mediate entanglement between two quantum systems must itself be quantum. On the other hand, Bose and his team discussed the details of a specific experiment, using two spin states to create the spatial superposition of the masses.
This isn’t a done deal by any means. Electromagnetic forces might interfere with the entanglement before researchers are able to measure the effects of quantum gravity. Even if the gravitational field is quantized, quantum gravity may be harder to detect than scientists predict. But if it does work, it could lead to quite a breakthrough.
There are a lot of theories on how gravity operates on the quantum level. It may originate from particles called gravitons, which would be carriers of gravity much like how photons carry electromagnetism. Quantum gravity and string theory have their own bends. The results of this experiment could help us sort quantum gravity out, and perhaps lead to a final theory, at which time, it’d be the dawning of a whole new understanding of the universe and how all its forces fit together.
To learn more about where we’re at with the Theory of Everything, click here:
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Richard Feynman once asked a silly question. Two MIT students just answered it.
Here's a fun experiment to try. Go to your pantry and see if you have a box of spaghetti. If you do, take out a noodle. Grab both ends of it and bend it until it breaks in half. How many pieces did it break into? If you got two large pieces and at least one small piece you're not alone.
But science loves a good challenge<p>The mystery remained unsolved until 2005, when French scientists <a href="http://www.lmm.jussieu.fr/~audoly/" target="_blank">Basile Audoly</a> and <a href="http://www.lmm.jussieu.fr/~neukirch/" target="_blank">Sebastien Neukirch </a>won an <a href="https://www.improbable.com/ig/" target="_blank">Ig Nobel Prize</a>, an award given to scientists for real work which is of a less serious nature than the discoveries that win Nobel prizes, for finally determining why this happens. <a href="http://www.lmm.jussieu.fr/spaghetti/audoly_neukirch_fragmentation.pdf" target="_blank">Their paper describing the effect is wonderfully funny to read</a>, as it takes such a banal issue so seriously. </p><p>They demonstrated that when a rod is bent past a certain point, such as when spaghetti is snapped in half by bending it at the ends, a "snapback effect" is created. This causes energy to reverberate from the initial break to other parts of the rod, often leading to a second break elsewhere.</p><p>While this settled the issue of <em>why </em>spaghetti noodles break into three or more pieces, it didn't establish if they always had to break this way. The question of if the snapback could be regulated remained unsettled.</p>
Physicists, being themselves, immediately wanted to try and break pasta into two pieces using this info<p><a href="https://roheiss.wordpress.com/fun/" target="_blank">Ronald Heisser</a> and <a href="https://math.mit.edu/directory/profile.php?pid=1787" target="_blank">Vishal Patil</a>, two graduate students currently at Cornell and MIT respectively, read about Feynman's night of noodle snapping in class and were inspired to try and find what could be done to make sure the pasta always broke in two.</p><p><a href="http://news.mit.edu/2018/mit-mathematicians-solve-age-old-spaghetti-mystery-0813" target="_blank">By placing the noodles in a special machine</a> built for the task and recording the bending with a high-powered camera, the young scientists were able to observe in extreme detail exactly what each change in their snapping method did to the pasta. After breaking more than 500 noodles, they found the solution.</p>
The apparatus the MIT researchers built specifically for the task of snapping hundreds of spaghetti sticks.
(Courtesy of the researchers)
What possible application could this have?<p>The snapback effect is not limited to uncooked pasta noodles and can be applied to rods of all sorts. The discovery of how to cleanly break them in two could be applied to future engineering projects.</p><p>Likewise, knowing how things fragment and fail is always handy to know when you're trying to build things. Carbon Nanotubes, <a href="https://bigthink.com/ideafeed/carbon-nanotube-space-elevator" target="_self">super strong cylinders often hailed as the building material of the future</a>, are also rods which can be better understood thanks to this odd experiment.</p><p>Sometimes big discoveries can be inspired by silly questions. If it hadn't been for Richard Feynman bending noodles seventy years ago, we wouldn't know what we know now about how energy is dispersed through rods and how to control their fracturing. While not all silly questions will lead to such a significant discovery, they can all help us learn.</p>
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In a recent study, researchers examined how Christian nationalism is affecting the U.S. response to the COVID-19 pandemic.
- A new study used survey data to examine the interplay between Christian nationalism and incautious behaviors during the COVID-19 pandemic.
- The researchers defined Christian nationalism as "an ideology that idealizes and advocates a fusion of American civic life with a particular type of Christian identity and culture."
- The results showed that Christian nationalism was the leading predictor that Americans engaged in incautious behavior.
A pastor at the chapel of the St. Josef Hospital on April 1, 2020 in Bochum, German
Sascha Schuermann/Getty Images<p>Christian nationalists, in general, believe the U.S. and God's will are tied together, and they want the government to embody conservative Christian values and symbols. As such, they also believe the nation's fate depends on how closely it adheres to Christianity.</p><p style="margin-left: 20px;">"Unsurprisingly then, in the midst of the COVID‐19 pandemic, conservative pastors prophesied God's protection over the nation, citing America's righteous support for President Trump and the prolife agenda," the researchers write.</p><p style="margin-left: 20px;">"Correspondingly, the link between Christian nationalism and God's influence on how COVID‐19 impacts America can be seen in proclamations about God's divine judgment for its immorality―with the logic being that God is using the pandemic to draw wayward America <em>back </em>to himself, which assumes the two belong together."</p><p>The logical conclusion to this kind of thinking: America can save itself not through cautionary measures, like mask-wearing, but through devotion to God. What's more, it stands to reason that Christian nationalists are less likely to trust the media and scientists, given that these sources are generally not concerned with promoting a conservative, religious view of the world.</p><p>(The researchers note that they're unaware of any research directly linking Christian nationalism to distrust of media sources, but that they're almost certain the two are connected.)</p>
Predicted values of Americans' frequency of incautious behaviors during the COVID‐19 pandemic across values of Christian nationalism
Perry et al.<p>In the new study, the researchers examined three waves of results from the Public and Discourse Ethics Survey. One wave of the survey was issued in May, and it asked respondents to rate how often they engaged in both incautious and precautionary behaviors.</p><p>Incautious behaviors included things like "ate inside a restaurant" and "went shopping for nonessential items," while precautionary behaviors included "washed my hands more often than typical" and "wore a mask in public."</p><p>To measure Christian nationalism, the researchers asked respondents to rate how strongly they agree with statements like "the federal government should advocate Christian values" and "the success of the United States is part of God's plan."</p><p>The results suggest that, compared to other groups, Christian nationalists are far less likely to wear masks, socially distance and take other precautionary measures amid the COVID-19 pandemic.</p><p style="margin-left: 20px;">"Christian nationalism was the leading predictor that Americans engaged in incautious behavior during the pandemic, and the second leading predictor that Americans avoided taking precautionary measures."</p><p>But that's not to say that religious beliefs are causing Americans to reject mask-wearing or social distancing. In fact, when the study accounted for Christian nationalist beliefs, the results showed that Americans with high levels of religiosity were likely to take precautionary measures for COVID-19.</p>
Limitations<p>Still, the researchers note that they're theorizing about the connections between Christian nationalism and COVID-19 behaviors, not documenting them directly. What's more, they suggest that certain experiences — such as having a family member that contracts COVID-19 — might change a Christian nationalist's behaviors during the pandemic.</p><p style="margin-left: 20px;">"Limitations notwithstanding, the implications of this study are important for understanding Americans' curious inability to quickly implement informed and reasonable strategies to overcome the threat of COVID‐19, an inability that has likely cost thousands of lives," they write.</p>
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