Today, February 11, is the International Day of Women and Girls in Science, the perfect day to remember Mileva Marić Einstein, a brilliant but largely unknown scientist. While her husband, Albert Einstein is celebrated as perhaps the best physicist of the century, one question about his career remains: How much did his first wife contribute to his groundbreaking science? While it is not possible to credit her with any specific part of his work, their letters and numerous testimonies presented in books dedicated to her [1−5] provide substantial evidence on how they collaborated from the time they met in 1896 up to their separation in 1914. They depict a couple united by a shared passion for physics, music and for each other. So here is her story.
Read more at https://arxiv.org/pdf/2002.08888.pdf
As a clinical technology, MRI offers unsurpassed flexibility to look inside the human body.
In 1977, inspired by the observation that cancerous and healthy tissues produced different nuclear magnetic resonance signals, Raymond Damadian, Michael Goldsmith, and Lawrence Minkoff performed the first MRI scan of a live human body. In the early days of clinical MRI, scans took hours and provided low spatial resolution, but they have become essential for distinguishing between healthy and diseased tissues. By its 40th anniversary, MRI was a must-have tool in hospitals and clinics of all sizes. And it has found applications in image-guided interventions and surgeries, radiation therapy, and focused ultrasound. Advances in technology, meanwhile, have pushed the envelope of scanner performance with improvements to speed and spatial resolution.
At the frontiers of MRI development, work is focused on fast, quantitative imaging. Clinical needs increasingly demand functional information—on heart-muscle contractions, brain activity,3 chemical concentrations in tumors,4 and blood flow in and out of tissue5—in addition to anatomical structures. New approaches must also maintain a patient’s comfort and safety; MRI is well-known for sparing patients any exposure to ionizing radiation, yet it is not without hazards.
HOW MRI WORKS
Have you ever wondered why we have never heard of psychics and palm readers winning millions of dollars in state or local lotteries or becoming Wall Street wolfs? Neither have I. Yet we are constantly bombarded by tabloid news on how vaccines cause autism (hint: they do not), or some unknown firm building a mega-drive that defies the laws of physics (nope, that drive does not work either). And the list continues on and on and on. Sometimes it looks quite legit as, say, various natural vitamin supplements that supposedly increase something that cannot be increased, or enhance something else that is most likely impossible to enhance by simply swallowing a few pills. Or constantly evolving diets that sure work giving a false relieve to those who really need to stop eating too much and actually pay frequent visits to a local gym. It is however understandable that most of us fall for such products and news just because we cannot be experts in everything, and we tend to trust various mass-media sources without even a glimpse of skepticism. So how can we distinguish between baloney statements and real exciting scientific discoveries and breakthroughs? In what follows I will try to do my best to provide a simple how-to user guide to debunking pseudoscientific claims.
Read more at https://arxiv.org/ftp/arxiv/papers/1906/1906.06165.pdf
The Heidelberg Laureate Forum Foundation presents the HLF Portraits: Edward Witten
Gary J. Ferland
What, if any, was Einstein’s biggest mistake, the one most affecting our physics today? There is a perhaps apocryphal story, recounted by George Gamow, that he counted his cosmological constant as his biggest blunder. We now know his hypothesized cosmological constant to be correct. His lifelong rejection of quantum mechanics, an interesting side-story in the evolution of 20th-century physics, is a candidate. None of these introduced difficulties in how our physics is done today. It can be argued that his biggest actual mistake, one that affects many subfields of physics and chemistry and bewilders students today, occurred in his naming of his A and B coefficients…
Read more at https://arxiv.org/pdf/1905.09276.pdf
My aim in this paper is twofold: (i) to distinguish two notions of naturalness employed in BSM physics and (ii) to argue that recognizing this distinction has methodological consequences. One notion of naturalness is an “autonomy of scales” requirement: it prohibits sensitive dependence of an effective field theory’s low-energy observables on precise specification of the theory’s description of cutoff-scale physics. I will argue that considerations from the general structure of effective field theory provide justification for the role this notion of naturalness has played in BSM model construction. A second, distinct notion construes naturalness as a statistical principle requiring that the values of the parameters in an effective field theory be “likely” given some appropriately chosen measure on some appropriately circumscribed space of models. I argue that these two notions are historically and conceptually related but are motivated by distinct theoretical considerations and admit of distinct kinds of solution.
Read more at https://arxiv.org/pdf/1812.08975.pdf