It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Wednesday, January 17, 2024
We need a staph vaccine: here’s why we don’t have one
Research from UC San Diego explains the clinical failure of dozens of candidate vaccines for one of the most common human infections; it also suggests a way to fix the problem
THIS ILLUSTRATION SHOWS SA (GOLDEN SPHERES) AND VARIOUS ANTIGENS AND ANTIBODIES. DOMINANT ANTIGENS (PURPLE) CAUSE SA TO PRODUCE NON-PROTECTIVE ANTIBODIES (RED WITH PURPLE TIPS). THESE NONPROTECTIVE ANTIBODIES OUTCOMPETE ANTIBODIES DERIVED FROM VACCINATION (GREEN WITH PURPLE TIPS). VACCINES TARGETING SUBDOMINANT ANTIGENS (BLUE) COULD HELP YIELD MORE PROTECTIVE ANTIBODIES (GREEN WITH BLUE TIPS), MAKING THE VACCINE MORE EFFECTIVE.
Staphylococcus aureus (SA) is an extremely common bacterial infection; about 30% of people have colonies of SA living in their nose. SA is often harmless, but it is also a leading cause of hospital-acquired and community-associated infections. A vaccine for SA would be a game-changer for public health, but for decades, all vaccine candidates for SA have failed in clinical trials despite successful preclinical studies in mice. Researchers at University of California San Diego School of Medicine have finally explained why.
In a new study, published January 16, 2024 in Cell Reports Medicine, they tested a new hypothesis that SA bacteria can trick the body into releasing non-protective antibodies when they first colonize or infect humans. When the individual is later vaccinated, these non-protective antibodies are preferentially recalled, making the vaccine ineffective.
SA has a unique relationship with humans. While it causes many dangerous health complications, including wound and bloodstream infections, the bacterium is also a normal part of the healthy human microbiome, where it lives peacefully in the nose and on the skin.
“SA has been with humans a long time, so it’s learned how to be part-time symbiont, part-time deadly pathogen,” said senior author George Liu MD, PhD, professor in the Department of Pediatrics at UC San Diego School of Medicine. “If we’re going to develop effective vaccines against SA, we need to understand and overcome the strategies it uses to maintain this lifestyle.”
The immune system releases protective antibodies in response to molecules it suspects are foreign, called antigens. These antibodies are then saved in the immune system’s memory, so the next time the immune system encounters that same antigen, it will generally recall its earlier immune response rather than mount a brand-new attack.
“This is an effective system for conferring long-term protection against pathogens, but it only works when the initial immune response to that pathogen was actually protective,” said co-lead author JR Caldera, PhD, who completed his doctoral research in the Liu Lab. “What sets SA apart is that the bacteria themselves have ways of evading the immune system from the moment they encounter us, and these evasive strategies are only reinforced by vaccination.”
While SA vaccines have unilaterally failed in clinical trials, they generally do well in preclinical studies of mice. In order to figure out why this is, the researchers collected blood serum from healthy volunteers, quantifying and purifying the anti-SA antibodies present in the samples. They then transferred these antibodies to mice to explore how protective they were against SA on their own, as well as how they influenced the efficacy of several clinically-tested SA vaccine candidates.
The researchers found that the vaccines were ineffective in mice that had been given human anti-SA antibodies, as well as mice that had been previously exposed to SA. However, in mice that had never been exposed to either SA or human antibodies, the vaccines worked. Unlike previous mouse studies of SA vaccines, the researchers’ results were consistent with those of failed clinical trials, suggesting that their experimental model could help predict the clinical success of SA vaccines while they are still being tested in preclinical mouse studies.
Further, they found that specific antibodies were to blame for the effect they observed. The antibodies that attack the cell walls of SA bacteria, which are the basis for most current SA vaccines, didn’t protect the mice against SA. By contrast, antibodies that target the toxins produced by SA were able to successfully neutralize them.
“One pathogen can have many different antigens that the immune system responds to, but there is a hierarchy as far as which antigen is dominant,” said co-lead author Chih Ming Tsai, PhD, a project scientist in the Liu Lab. “Most vaccines are based on the dominant antigen to trigger the strongest possible immune response. But our findings suggest that for SA, the rules are different, and it is more beneficial to target so-called subdominant antigens, which triggered a weak immune response in the first place.”
In addition to exploring the possibility of targeting new antigens with future SA vaccines, the researchers are also interested in exploring the deeper question at play here: why is the natural human immune response to this bacterium so ineffective to begin with?
“Somehow, SA is able to trick our immune system, and figuring out how will help us improve existing SA vaccines and develop new ones,” said Liu. “More broadly, these findings suggest a whole new way of reevaluating failed vaccines, which could have implications well beyond this one bacterium.”
Co-authors of the study include: Desmond Trieu, Cesia Gonzalez, Irshad A. Hajam, Xin Du and Brian Lin at UC San Diego.
This study was funded, in part, by the National Institute of Health (grants R01AI127406, R01AI144694 and R01AI181321).
This graphical abstract shows the experimental approach used by the researchers to study immune responses to SA vaccination. Vaccines targeting subdominant antigens, such as toxins produced by the bacteria, conferred more protection than vaccines targeting dominant antigens.
About The Study: Based on four simulation models, breast cancer screening, treatment of stage I to III breast cancer, and treatment of metastatic breast cancer were each associated with reduced breast cancer mortality between 1975 and 2019 in the U.S.
Authors: Sylvia K. Plevritis, Ph.D., of the Stanford University School of Medicine in Stanford, California, is the corresponding author.
Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.
About The Study: This systematic review and meta-analysis of 42 eligible studies, including 17 among children (n = 45,851) and 25 among adults (n = 268,095), found a positive association between intake of 100% fruit juice and weight gain in children. Analysis of cohort studies in adults found a significant positive association among studies unadjusted for total energy, suggesting potential mediation by calories; an analysis of trials in adults found no significant association between 100% fruit juice consumption and body weight. The findings support guidance to limit consumption of fruit juice to prevent the intake of excess calories and weight gain.
Authors: Vasanti S. Malik, M.Sc., Sc.D., of the University of Toronto, is the corresponding author.
Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.
About The Study: The results of this survey study involving 4,119 currently competing U.S. college athletes suggest that interpersonal violence is associated with marked changes in the psychosocial health and emotional well-being of college athletes, particularly those who identify as female and with non-heterosexual sexual orientations. Variations in coaching style have the potential to alter these associations. Ongoing efforts are needed to leverage the unique position that coaches hold to help reduce interpersonal violence and create safe places where all college athletes can thrive.
Authors: Yetsa A. Tuakli-Wosornu, M.D., M.P.H., of the Yale School of Public Health in New Haven, Connecticut, is the corresponding author.
Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.
RESEARCHERS FROM THE UNIVERSITY OF COLORADO ANSCHUTZ MEDICAL CAMPUS HAVE FOUND THAT A TEAM INTERVENTION, PROVIDED BY PHONE, LEADS TO PERSISTENT IMPROVEMENTS IN DEPRESSION, ANXIETY, AND QUALITY OF LIFE FOR PEOPLE MANAGING CHRONIC ILLNESSES. ADDITIONALLY, RESEARCHERS FOUND THAT THE IMPROVEMENT IN QUALITY OF LIFE RESULTS LAST MONTHS AFTER INTERVENTION CONCLUDES.
CREDIT: UNIVERSITY OF COLORADO ANSCHUTZ MEDICAL CAMPUS
AURORA, Colo.(January 16, 2024) – Researchers from the University of Colorado Anschutz Medical Campus have found that a team intervention, provided by phone, leads to persistent improvements in depression, anxiety, and quality of life for people managing chronic illnesses. Additionally, researchers found that the improvement in quality of life results last months after intervention concludes.
In a study, published today in JAMA, researchers observe the impact a telecare intervention program, called ADAPT, has on veterans suffering from poor quality of life as a result of existing chronic illnesses, such as chronic obstructive pulmonary disease (COPD), heart failure (HF) and interstitial lung disease (ILD). This program provides palliative care that is not widely available and tackles health concerns that may be missed in standard appointments. Nurses and social workers reach out to study participants with structured questions and assistance, then discuss responses with a team of doctors, including specialists, to determine how best to address concerns with follow-up calls to track progress.
“While we do a great job caring for these patients’ illnesses, we can do more for quality of life. Many have persistent symptoms, such as depression, anxiety, shortness of breath, and sleep problems that can make living with these illnesses very difficult and have been associated with earlier death” says David Bekelman, MD, MPH, professor at the University of Colorado School of Medicine and study lead author. “Palliative care can help. However, access to outpatient palliative care specialists is limited to non-existent, and new, scalable ways to provide early palliative care are needed.”
For adults with COPD, HF or ILD at high risk of hospitalization and death and poor quality of life, this program demonstrated early, persistent and clinically meaningful improvements in depression, anxiety, and quality of life. Additionally, while ADAPT lasted for 4 months, Bekelman and researchers saw positive results early that lasted for many months after the program ended.
“There are people who endure persistent symptoms and poor quality of life despite great treatments. We need to fill in the gaps and provide more for these patients,” says Bekelman who worked with the VA of Eastern Colorado Puget Sound Health Care Systems to conduct this research to conduct this research. “This innovative team care model is adaptable, scalable and can help make life better for people living with these illnesses. This program demonstrates that even a short amount of time providing structured telecare results in increased quality of life months after the calls end.”
About the University of Colorado Anschutz Medical Campus
The University of Colorado Anschutz Medical Campus is a world-class medical destination at the forefront of transformative science, medicine, education and patient care. The campus encompasses the University of Colorado health professional schools, more than 60 centers and institutes, and two nationally ranked independent hospitals - UCHealth University of Colorado Hospital and Children's Hospital Colorado - that treat more than two million adult and pediatric patients each year. Innovative, interconnected and highly collaborative, the University of Colorado Anschutz Medical Campus delivers life-changing treatments, patient care and professional training and conducts world-renowned research fueled by over $704 million in research grants. For more information, visit www.cuanschutz.edu.
Largest-ever study of palliative care demonstrates scalable strategy to increase support for seriously ill patients in the hospital
“Default orders” in electronic medical record nearly tripled palliative care consultation rates for patients with chronic obstructive pulmonary disease, dementia, or kidney failure
PHILADELPHIA – Ordering a palliative care consultation by “default” – via an automatic order programmed into the electronic medical record that doctors may cancel if they choose – is an effective strategy to give more hospitalized patients the opportunity to benefit from palliative care, and sooner, according to a new study led by researchers from the Perelman School of Medicine at the University of Pennsylvania. Palliative care is specialized medical care focused on relieving the symptoms and stress of a serious illness and improving quality of life, in alignment with a patient’s individual goals, values, and priorities. By changing the process for ordering palliative care consultation from doctors opting in and actively placing an order to having the opportunity to opt out and cancel an automatic order, the investigators increased palliative care consultation rates from 16.6 percent to 43.9 percent and decreased the time to consultation by 1.2 days in the largest-ever study of inpatient palliative care, published today in JAMA.
“While early palliative care consultation could help many patients with chronic serious illnesses better understand their diagnosis and align their treatment choices to their individual care goals, there's never been an established approach to realizing that goal at scale. We found that a simple, pre-programmed order within the electronic medical record can get more palliative care to more people more quickly,” said lead author Kate Courtright, MD, MS, an assistant professor of Critical Care and Palliative Medicine. “This strategy was low-cost and easily implemented in community hospitals, which is where most Americans receive their health care.”
The study included more than 34,000 patients with chronic obstructive pulmonary disease (COPD), dementia, or kidney failure at 11 hospitals in eight states, all part of one of the nation’s largest non-profit health systems. Although palliative care consultation is recommended for millions of Americans with serious illnesses, many patients aren’t referred to palliative care or only receive a consultation at the end of life. Patients with COPD, dementia, and kidney failure have been underrepresented in past studies of palliative care delivery, which have largely focused on patients with cancer or heart failure in academic health centers. But these patients often experience challenges with coping, as well as breathlessness, anxiety, pain, and other symptoms that palliative care can help address through medications, other treatments, and/or referrals to other specialists. Palliative care can be given at any stage of treatment, including along with therapy intended to cure the condition.
Each of the 11 hospitals in the study had an established palliative care program, but to keep the study as realistic as possible, hospitals were neither encouraged to nor prohibited from increasing or decreasing palliative care staffing during the study. Over the course of the study, which took place between March 2016 and November 2018, the hospitals began enrolling patients to the study under usual care (data collected, but no intervention) and transitioned to the intervention phase (default orders via the electronic health record) over time, in a randomly determined order. During the intervention phase, clinicians canceled the default for fewer than 10 percent of patients for whom it was generated. Clinicians could also place their own order for a palliative care consultation at any point during the study.
“Our results suggest that the default order strategy was generally acceptable to clinicians, which is important because if we want to reach as many eligible patients as possible, we need to design approaches that are feasible for ‘real-world’ practice and not just in the research setting,” Courtright said.
Implementing default orders did not impact how long patients stayed in the hospital compared to usual care, perhaps because, even in the intervention group, less than half of patients actually received a consultation from a palliative care specialist. This may be due to limited staff resources or other factors. Anticipating that default orders would not necessarily guarantee a consultation, the study authors planned for a secondary outcomes analysis and found that for patients who only received palliative care consultation thanks to the default order, such care reduced the median length of stay by 9.6 percent. Additionally, the default orders led to more patients being discharged from the hospital to hospice care without affecting mortality, suggesting that such orders improved the quality and patient-centeredness of end-of-life care.
“We know that health care systems have limited resources and need more evidence to guide future scaling and delivery of inpatient palliative care in an equitable and cost-effective manner,” said senior author Scott D. Halpern, MD, PhD, the John M. Eisenberg Professor of Medicine, Epidemiology, and Medical Ethics and Health Policy. “As we build on this work, our goal is to continuously improve inpatient palliative care so that all patients and families facing a serious illness have access to the support they need to carry on with their daily lives throughout their treatment journey.”
The study was supported by the National Institutes of Aging (UH3AG050311) and the Otto Haas Charitable Trust.
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Penn Medicine is one of the world’s leading academic medical centers, dedicated to the related missions of medical education, biomedical research, excellence in patient care, and community service. The organization consists of the University of Pennsylvania Health System and Penn’s Raymond and Ruth Perelman School of Medicine, founded in 1765 as the nation’s first medical school.
The Perelman School of Medicine is consistently among the nation's top recipients of funding from the National Institutes of Health, with $550 million awarded in the 2022 fiscal year. Home to a proud history of “firsts” in medicine, Penn Medicine teams have pioneered discoveries and innovations that have shaped modern medicine, including recent breakthroughs such as CAR T cell therapy for cancer and the mRNA technology used in COVID-19 vaccines.
The University of Pennsylvania Health System’s patient care facilities stretch from the Susquehanna River in Pennsylvania to the New Jersey shore. These include the Hospital of the University of Pennsylvania, Penn Presbyterian Medical Center, Chester County Hospital, Lancaster General Health, Penn Medicine Princeton Health, and Pennsylvania Hospital—the nation’s first hospital, founded in 1751. Additional facilities and enterprises include Good Shepherd Penn Partners, Penn Medicine at Home, Lancaster Behavioral Health Hospital, and Princeton House Behavioral Health, among others.
Penn Medicine is an $11.1 billion enterprise powered by more than 49,000 talented faculty and staff.
Intensive care units (ICUs) commonly have to provide palliative care to patients. But not every medical center has special expertise in palliative medicine. Can telemedicine consultations further improve the palliative care provided in ICU settings? An international research consortium headed by Charité – Universitätsmedizin Berlin is studying this question. Their newly launched project, titled “Enhancing palliative care in ICU” (EPIC), is receiving about 6.3 million euros in funding from the European Commission for a period of five years.
Alleviating pain and other symptoms for seriously ill patients to preserve and support their remaining lifespans and quality of life is the goal of palliative medicine. It is an important and established part of intensive care. However, if the patient’s disease and symptoms are very complex, it can be helpful for ICU staff to turn to palliative medicine specialists for advice on specific cases. “But not every hospital has in-house expertise in palliative medicine,” says Prof. Claudia Spies, Director of the Department of Anesthesiology and Intensive Care Medicine at Charité. “Systematic use of telemedicine that allows experts to be brought in virtually, and thus fast and from anywhere, could bring even more improvement in the palliative care provided in ICU settings.”
A practical model with three strands: continuing education, checklists, telemedicine
So how much benefit do telemedicine consultations with palliative medicine experts bring in comparison to the palliative care typically provided in an intensive care unit? A team of researchers is working to answer that question in the EPIC project. “Before the telemedicine consultation phase starts, the ICU clinical staff will first receive training in palliative medicine,” explains Spies, who is heading up the research project. “We’re also working on checklists to help the teams identify the patients who could benefit from specialized palliative care as early as possible.” Some 2,000 patients and their families are participating in the research project, which is being carried out at seven clinical centers with palliative medicine and 23 multidisciplinary ICUs in five European countries.
“EPIC is bringing together clinicians and researchers from the areas of palliative and intensive care, social sciences, nursing, ethics, and health economics with the goal of implementing a harmonized practical model of palliative care at ICUs, and not just in one country, but all across Europe,” Spies explains. “We hope our project will help us identify recommended actions that we can pass along to specialized organizations and that can be included in initial and continuing education and training for the next generation of intensive care staff across multiple professions.”
Shorter ICU stays
Studies show that integrating palliative medicine as soon as possible shortens the amount of time patients spend in intensive care, although mortality remains the same. With this in mind, one of the researchers’ goals in EPIC is to reduce the time patients spend in the ICU – which not only has benefits from a health economics standpoint, but is also of immeasurable value for the patients themselves. “When patients with severe and incurable diseases receive optimum palliative care, then they hopefully won’t have to spend their last days in the ICU, unless there’s a very serious reason. This can be a blessing for them and their families during this extremely critical and highly vulnerable phase at the end of life,” Spies says. “And palliative care is also helpful for people with severe or chronic disease who are not approaching the end of life. People often confuse palliative medicine with hospice, but they aren’t the same. About half of patients can be discharged and go home with specialized palliative treatment. So improving palliative care across the board would benefit all of the patients in the ICU.”
Another of the researchers’ aims in EPIC is to study how well patients and family members respond to palliative medicine that is provided with telemedicine support. They also plan to establish a group for patients and families to share their stories and information and provide mutual support.
About EPIC The research consortium is headed up by Prof. Claudia Spies, Director of the Department of Anesthesiology and Intensive Care Medicine on Campus Charité Mitte and Campus Virchow-Klinikum. Funding is being provided as part of the EU’s Horizon Europe framework program. The other partners in the consortium are: General University Hospital in Prague (Czech Republic), Hebrew University of Jerusalem (Israel), Heinrich-Heine-Universität Düsseldorf (Germany), King’s College Hospital (United Kingdom), KU Leuven (Belgium), Martin Luther University Halle-Wittenberg (Germany), the Faculty of Medicine of the University of Basel (Switzerland), National and Kapodistrian University of Athens (Greece), Università degli Studi di Perugia (Italy), the University of Southern Denmark (Denmark), Universitätsklinikum Erlangen (Germany), the European Association for Palliative Care (Belgium), the European Society of Anaesthesiology and Intensive Care (Belgium), and tp21 GmbH (Germany). There are plans to start a cooperation with a group representing patients and families.
Quantum computing and machine learning are effective tools in fluid dynamics
Quantum support vector machines classify flow separation better than classical counterparts
To prevent aircraft stalls, engineers have long studied the flow of air over airfoils such as airplane wings to detect the angles when flow separation occurs. Recently, a team of researchers at Shanghai Jiao Tong University including Xi-Jun Yuan and Zi-Qiao Chen investigated the use of quantum computing in connection with machine learning as a more accurate way of solving such problems. Their research was published Nov. 21 in Intelligent Computing, a Science Partner Journal.
The use of a quantum support vector machine rather than a classical support vector machine increased the accuracy of classification of flow separation from 81.8% to 90.9% and increased the accuracy of classification of the angle of attack from 67.0% to 79.0%. These results help show that using quantum computing methods for fluid dynamics problems could be faster and more accurate than using classical computing methods, especially because the datasets in such contexts are large. Potential applications of quantum support vector machines in addition to aircraft design include underwater navigation and target tracking.
The researchers performed two classification tasks. The first was a binary classification on a small dataset to detect whether or not flow separation had occurred. A small dataset was chosen because it is difficult to achieve high-accuracy classification for small datasets. Data for this task were collected from pressure sensors on an airfoil in a wind tunnel with different airspeeds and angles of attack. The dataset consists of 45 multidimensional points: 27 cases without flow separation and 18 cases with flow separation. This dataset was divided into 34 points for training and 11 points for testing.
The second task was more complex. It classified the angle of attack of the airfoil after flow separation into one of four classes. To achieve this, the problem was broken into four one-against-all classification problems, with a binary in-or-out classifier for each of the four classes. Data for this task were created by simulation. The dataset consists of 63 multidimensional points obtained by sampling. This dataset was divided into 43 points for training and 20 for testing. The training and testing process was repeated 10 times with different combinations of training and test data, and the average accuracy of 10 tests was obtained.
The particular type of classification algorithm chosen by the researchers is a quantum-annealing-based supervised machine learning algorithm called a support vector machine. The quantum annealer they used was the D-Wave Advantage 4.1 system, a physical quantum computing device.
Quantum annealing implementations of support vector machines have demonstrated better performance than their classical counterparts, which are structurally simple and robust, but have high storage and computation costs and thus do not scale up easily.
Quantum annealing is an optimization process that uses quantum fluctuations to look for a global minimum among a set of solutions. Because the process generates multiple good candidates for the global minimum, it can achieve more accurate results than other optimization algorithms, which are more likely to get stuck at a local minimum.
Results of the flow classification problem.
A. and B. Decision plane obtained by classical and quantum support vector machines for the same dataset. The color represents the value of the training data decision function and the black dotted line marks the decision boundary. Test set data are represented by circles. C. Comparison of the performance of quantum and classical classifiers on flow separation tasks.
Quantum Support Vector Machines for Aerodynamic Classification
Experiment could test quantum nature of large masses for the first time
An experiment outlined by a UCL-led team could test whether relatively large masses have a quantum nature, resolving the question of whether quantum mechanical description works at a much larger scale than that of particles and atoms.
An experiment outlined by a UCL (University College London)-led team of scientists from the UK and India could test whether relatively large masses have a quantum nature, resolving the question of whether quantum mechanical description works at a much larger scale than that of particles and atoms.
Quantum theory is typically seen as describing nature at the tiniest scales and quantum effects have not been observed in a laboratory for objects more massive than about a quintillionth of a gram, or more precisely 10^(-20)g.
The new experiment, described in a paper published in Physical Review Letters and involving researchers at UCL, the University of Southampton and the Bose Institute in Kolkata, India, could in principle test the quantumness of an object regardless of its mass or energy.
The proposed experiment exploits the principle in quantum mechanics that the act of measurement of an object can change its nature. (The term measurement encompasses any interaction of the object with a probe – for instance, if light shines on it, or if it emits light or heat).
The experiment focuses on a pendulum-like object oscillating like a ball on a string. A light is shone on one half of the area of oscillation, revealing information about the location of the object (i.e., if scattered light is not observed, then it can be concluded that the object is not in that half). A second light is shone, showing the location of the object further along on its swing.
If the object is quantum, the first measurement (the first flash of light) will disturb its path (by measurement induced collapse -- a property inherent to quantum mechanics), changing the likelihood of where it will be at the second flash of light, whereas if it is classical then the act of observation will make no difference. Researchers can then compare scenarios in which they shine a light twice to ones where only the second flash of light occurs to see if there is a difference in the final distributions of the object.
Lead author Dr Debarshi Das (UCL Physics & Astronomy and the Royal Society) said: “A crowd at a football match cannot affect the result of the game simply by staring strongly. But with quantum mechanics, the act of observation or measurement itself changes the system.
“Our proposed experiment can test if an object is classical or quantum by seeing if an act of observation can lead to a change in its motion.”
The proposal, the researchers say, could be implemented with current technologies using nanocrystals or, in principle, even using mirrors at LIGO (Laser Interferometer Gravitational-Wave Observatory) in the United States which have an effective mass of 10kg.
The four LIGO mirrors, which each weigh 40kg but together vibrate as if they were a single 10kg object, have already been cooled to the minimum-energy state (a fraction above absolute zero) that would be required in any experiment seeking to detect quantum behaviour.
Senior author Professor Sougato Bose (UCL Physics & Astronomy) said: “Our scheme has wide conceptual implications. It could test whether relatively large objects have definite properties, i.e., their properties are real, even when we are not measuring them. It could extend the domain of quantum mechanics and probe whether this fundamental theory of nature is valid only at certain scales or if it holds true for larger masses too.
“If we do not encounter a mass limit to quantum mechanics, this makes ever more acute the problem of trying to reconcile quantum theory with reality as we experience it.”
In quantum mechanics, objects do not have definite properties until they are observed or interact with their environment. Prior to observation they do not exist in a definite location but may be in two places at once (a state of superposition). This led to Einstein’s remark: “Is the moon there when no one is looking at it?”
Quantum mechanics may seem at odds with our experience of reality but its insights have helped the development of computers, smartphones, broadband, GPS, and magnetic resonance imaging.
Most physicists believe quantum mechanics holds true at larger scales, but is merely harder to observe due to the isolation required to preserve a quantum state. To detect quantum behaviour in an object, its temperature or vibrations must be reduced to its lowest possible level (its ground state) and it must be in a vacuum so that nearly no atoms are interacting with it. That is because a quantum state will collapse, a process called decoherence, if the object interacts with its environment.
The new proposed experiment is a development of an earlier quantum test devised by Professor Bose and colleagues in 2018. A project to conduct an experiment using this methodology, which will test the quantum nature of a nanocrystal numbering a billion atoms, is already underway, funded by the Engineering and Physical Sciences Research Council (EPSRC) and led by the University of Southampton.
That project already aims for a jump in terms of mass, with previous attempts to test the quantum nature of a macroscopic object limited to hundreds of thousands of atoms. The newly published scheme, meanwhile, could be achieved with current technologies using a nanocrystal with trillions of atoms.
The new paper was co-authored by Dr Das and Professor Bose at UCL along with Professor Dipankar Home of India’s Bose Institute (who also co-authored the 2018 paper) and Professor Hendrik Ulbricht of the University of Southampton.
JOURNAL
Physical Review Letters
METHOD OF RESEARCH
Computational simulation/modeling
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Mass-independent scheme to test the quantumness of a massive object
