Milestone on the road to the ‘quantum internet’

Researchers at the University of Stuttgart teleport quanta between photons from two distant light sources, achieving a decisive breakthrough in the development of quantum repeaters

Universitaet Stuttgart

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

 

image: 

Physicists from research groups at the University of Stuttgart, Saarbrücken, and Dresden conducting an experiment on quantum teleportation (from left to right: Tobias Bauer, Marlon Schäfer, Caspar Hopfmann, Stefan Kazmaier, Tim Strobel, and Simone Luca Portalupi).

view more 

Credit: Julian Maisch

Everyday life on the internet is insecure. Hackers can break into bank accounts or steal digital identities. Driven by AI, attacks are becoming increasingly sophisticated. Quantum cryptography promises more effective protection. It makes communication secure against eavesdropping by relying on the laws of quantum physics. However, the path toward a quantum internet is still fraught with technical hurdles. Researchers at the Institute of Semiconductor Optics and Functional Interfaces (IHFG) at the University of Stuttgart have now made a decisive breakthrough in one of the most technically challenging components, the ‘quantum repeater’. They report their results in Nature Communications (DOI: 10.1038/s41467-025-65912-8).

Nanometer-sized semiconductor islands for information transfer

“For the first time worldwide, we have succeeded in transferring quantum information among photons originating from two different quantum dots,” says Prof. Peter Michler, head of the IHFG and deputy spokesperson for the Quantenrepeater.Net (QR.N) research project. What is the background? Whether WhatsApp or video stream, every digital message consists of zeros and ones. Similarly, this also applies to quantum communication in which individual light particles serve as carriers of information. Zero or one is then encoded in two different directions of polarization of the photons (i.e., their orientation in the horizontal and vertical directions or in a superposition of both states). Because photons follow the laws of quantum mechanics, their polarization cannot always be completely read out without leaving traces. Any attempt to intercept the transmission would inevitably be detected.

Making the quantum internet ready for the fiber-optic infrastructure

Another challenge: An affordable quantum internet would use optical fibers—just like today’s internet. However, light has only a limited range. Conventional light signals, therefore, need to be renewed approximately every 50 kilometers using an optical amplifier. Because quantum information cannot simply be amplified or copied and forwarded, this does not work in the quantum internet. However, quantum physics allows information to be transferred from one photon to another as long as the information stays unknown. This process is referred to as quantum teleportation.

Quantum repeaters as nodes for information transmission

Building on this, physicists are developing quantum repeaters that renew quantum information before it is absorbed in the optical fiber. They are to serve as nodes for the quantum internet. However, there are considerable technical hurdles. To transmit quantum information via teleportation, the photons must be indistinguishable (i.e., they must have approximately the same temporal profile and color). This proves extremely difficult because they are generated at different locations from different sources. “Light quanta from different quantum dots have never been teleported before because it is so challenging,” says Tim Strobel, scientist at the IHFG and first author of the study. As part of QR.N, his team has developed semiconductor light sources that generate almost identical photons. “In these semiconductor islands, certain fixed energy levels are present, just like in an atom,” says Strobel. This allows individual photons with defined properties to be generated at the push of a button. “Our partners at the Leibniz Institute for Solid State and Materials Research in Dresden have developed quantum dots that differ only minimally,” says Strobel. This means that almost identical photons can be generated at two locations.

Information is “beamed” from one photon to another

At the University of Stuttgart, the team succeeded in teleporting the polarization state of a photon originating from one quantum dot to another photon from a second quantum dot. One quantum dot generates a single photon, the other an entangled photon pair. “Entangled” means that the two particles constitute a single quantum entity, even when they are physically separated. One of the two particles travels to the second quantum dot and interferes with its light particle. The two overlap. Because of this superposition, the information of the single photon is transferred to the distant partner of the pair. Instrumental for the success of the experiment were “quantum frequency converters”, which compensate residual frequency differences between the photons. These converters were developed by a team led by Prof. Christoph Becher, an expert in quantum optics at Saarland University.

Improvements for reaching considerably greater distances

“Transferring quantum information between photons from different quantum dots is a crucial step toward bridging greater distances,” says Michler. In the Stuttgart experiment, the quantum dots were separated only by an optical fiber of about 10 m length. “But we are working on achieving considerably greater distances,” says Strobel. In earlier work, the team had shown that the entanglement of the quantum dot photons remains intact even after a 36-kilometer transmission through the city center of Stuttgart. Another aim is to increase the current success rate of teleportation, which currently stands at just over 70%. Fluctuations in the quantum dot still lead to slight differences in the photons. “We want to reduce this by advancing semiconductor fabrication techniques,” says Strobel. “Achieving this experiment has been a long-standing ambition — these results reflect years of scientific dedication and progress,” says Dr. Simone Luca Portalupi, group leader at the IHFG and one of the study coordinators. “It’s exciting to see how experiments focused on fundamental research are taking their first steps toward practical applications.”

Quantenrepeater.Net research network

Research into quantum repeaters is funded by the Federal Ministry of Research, Technology and Space (BMFTR) as part of the “Quantenrepeater.Net (QR.N)” project. Coordinated by Saarland University, the QR.N consortium brings together 42 partners from research institutions, universities, and industry to explore and test quantum repeater technology in optical fiber networks. The project builds on the results of the BMFTR-funded (former known as BMBF) “Quantenrepeater.Link (QR.X)” initiative, which, led by Saarland University, laid the groundwork for developing a nationwide quantum repeater between 2021 and 2024. Physicists at the University of Stuttgart have played a major role in shaping both research consortia. The experiments on quantum teleportation were conducted under the coordination of the Institute of Semiconductor Optics and Functional Interfaces (IHFG) at the University of Stuttgart, with contributions from the Leibniz Institute for Solid State and Materials Research (IFW) in Dresden and the Quantum Optics research group at Saarland University.

Caption

Tobias Bauer (left) and Marlon Schäfer (right) from Saarland University and Tim Strobel (center) from the University of Stuttgart preparing for an experiment with mobile quantum frequency converters.

Credit

Julian Maisch

---

Journal

Nature Communications

DOI

10.1038/s41467-025-65912-8 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Telecom-wavelength quantum teleportation using frequency-converted photons from remote quantum dots

Article Publication Date

17-Nov-2025

 

Replacing meat, dairy, and eggs with grains, legumes, and other plant foods reduces greenhouse gas emissions by 51%, new research shows

Physicians Committee for Responsible Medicine

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

WASHINGTON, D.C.— A low-fat vegan diet is associated with a significant reduction in greenhouse gas emissions (GHGE) and cumulative energy demand (CED) compared to the Standard American Diet, according to research by the Physicians Committee for Responsible Medicine published in JAMA Network Open.

The study showed a 51% reduction in GHGE (by 1,313 g CO2-eq/person per day) and a 51% reduction in CED (by 8,194 kJ/person per day), mainly attributable to reduced meat consumption, followed by reduced dairy consumption in GHGE, and reduced egg intake in CED. To put this in perspective, 1,313 grams of CO2e is equivalent to driving a gas-powered vehicle about 4.3 miles. And this reduction in GHGE is happening every day people eat plant-based meals.

“As awareness of its environmental impact grows, swapping plant foods for animal products will be as ubiquitous as reduce, reuse, and recycle,” says Hana Kahleova, MD, PhD, the author of the paper and director of clinical research at the Physicians Committee for Responsible Medicine. A recent survey found that nearly half of Americans would consider eating a plant-based diet to help reduce greenhouse gas emissions.

“We know whole food, plant-based diets are better for our health and the environment,” she adds. “This analysis shows us just how impactful our daily food choices are.”

This research is published just after the EAT-Lancet Commission report issued Oct. 2 said that a global shift toward “healthier diets” that include more fruits, vegetables, and nuts and less red meat is necessary to cut greenhouse gas emissions.

The new research is a secondary analysis of a Physicians Committee study, which found that a low-fat plant-based diet is an effective tool for reducing body weight and increasing insulin sensitivity and postprandial metabolism.

For this secondary analysis of environmental impact of diet, intakes from dietary records were linked to the USDA Food Commodity Intake Database and the database of Food Impacts on the Environment for Linking to Diets.

“Prior research has shown that red meat, in particular, has an outsized impact on energy use compared to grains, legumes, fruits, and vegetables,” Dr. Kahleova says. “Our randomized study shows just how much a low-fat vegan diet is associated with a substantial reduction in greenhouse gas emissions and energy use, significant drivers of climate change.”  

-30-

Founded in 1985, the Physicians Committee for Responsible Medicine is a nonprofit organization that promotes preventive medicine, conducts clinical research, and encourages higher standards for ethics and effectiveness in education and research.

 

---

Journal

JAMA Network Open

DOI

10.1001/jamanetworkopen.2025.43871 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Vegan Diet, Greenhouse Gas Emissions, and Cumulative Energy Demand A Secondary Analysis of a Randomized Clinical Trial

Article Publication Date

18-Nov-2025

MALE SEXUALITY

Edging, tab-jumping, and more: Researchers identify behavioral markers of problematic pornography use

Study categorized problematic pornography use based on data from over 2,000 male consumers

D'Or Institute for Research and Education

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

Digital technology—and especially the Internet—has revolutionized the way we work, study, socialize, and entertain ourselves. Alongside the global increase in screen time, both public and academic attention to potentially addictive digital behaviors has grown.

One such behavior is online pornography consumption. A study published in Addictive Behaviors, conducted by researchers from Monash University (Australia), the D’Or Institute for Research and Education (IDOR), and the Federal University of Rio de Janeiro (UFRJ), investigated problematic pornography use (PPU), particularly in men.

Defining PPU as a Disorder

Problematic pornography use is marked by difficulty controlling consumption, even when the person recognizes negative consequences. A 2018 survey showed that over 10% of Brazil’s population reported viewing pornography, with 76% identifying as male. In the U.S., approximately 11% of men and 3% of women describe themselves as addicted to it.

Because the issue disproportionately affects men—and psychological dynamics differ by gender—the study gathered data from over 2,000 male participants to explore behavioral intensifiers and possible pathways to addiction.

Understanding PPU through User Behavior

One of the major challenges in treating PPU is the lack of consensus around its classification—whether it is a form of compulsive sexual behavior or part of Internet-related behavioral addiction.

To contribute to this debate, researchers examined various intensity indicators, including qualitative and quantitative tolerance, binge sessions (lasting at least two hours and/or involving multiple orgasms), delayed orgasm (edging), and frequent switching between content (tab-jumping). Participants had consumed online pornography at least once in the past 12 months and were recruited from online platforms in the U.S. and U.K.

The survey assessed difficulties in reducing use, impulsivity, and use of pornography to cope with emotions. Specific questions focused on the frequency of binge sessions, edging (“How often do you delay orgasm to prolong the session?”), and tab-jumping (“How often do you switch to new content during a session?”).

Key Findings

The study found that increased time spent on pornography was closely associated with other intensity indicators, such as lack of control and impulsivity. This suggests that greater engagement—combined with diminished pleasure due to repeated exposure—could be a key feature of PPU.

Notably, binge sessions, tab-jumping, and edging were strongly linked to problematic use. The researchers highlighted that PPU is more closely related to Internet addiction than to offline sex addiction, with digital novelty playing a central role in usage patterns.

Tolerance may serve as a mediator between intensified pornography use and behavioral loss of control. The study suggests that individuals with PPU often seek novelty during sessions, reinforcing compulsive behaviors.

Therapeutic Targets and Future Directions

This study is the first to quantify specific behaviors such as binge sessions, edging, and tab-jumping in relation to PPU. Measuring these traits may help guide both clinical and self-help interventions.

Tolerance to content, in particular, may be a promising therapeutic target, given its mediating role in prolonged sessions and the pursuit of increasingly intense material.

Ultimately, the study offers new perspectives on how certain behaviors escalate problematic pornography use and opens paths for more effective treatments and future scientific research.

---

Journal

Addictive Behaviors

DOI

10.1016/j.addbeh.2024.108048 

Severity of obesity closely associated with likelihood of disease burden in US national study

Pennington Biomedical researchers discover direct relationship upon examining association between obesity and cardiometabolic and renal diseases

Pennington Biomedical Research Center

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

 

image: 

Dr. Florina Corpodean presents "Associations of Obesity Severity with Cardiometabolic and Renal Disease Burden in the United States," at ObesityWeek 2025.

view more 

Credit: Pennington Biomedical Research Center

Obesity severity is incrementally associated with a broad range of cardiometabolic and renal disease burden, as discovered by researchers at Pennington Biomedical Research Center. Recently published in Obesity, the paper “Association of Obesity Severity with Cardiometabolic and Renal Disease Burden in the United States,” explored the relationship through a cross-sectional study of data from the U.S. Behavioral Risk Factor Surveillance System survey. 

In exploring the survey results, which contained data on more than 5 million people captured between 2011 and 2023, researchers calculated odds ratios for the diagnosis of diabetes, hypertension, hyperlipidemia, kidney disease, myocardial infarction, stroke and coronary artery disease across different classes of obesity. The obesity classifications were Class I (body mass index, or BMI, between 30.0 and 34.9), Class II (35.0 and 39.9), Class III (40.0 to 49.9) and Class IV (50.0 or greater). A higher BMI was associated with increased odds for all conditions, with Class IV exhibiting notably elevated odds for diabetes, hypertension and kidney disease.

“The data show an increased likelihood of a wide array of common metabolic diseases that increase with obesity severity,” said Dr. Florina Corpodean, Postdoctoral Research Fellow in Pennington Biomedical’s Metamor Institute. “A clear, gradual increase in disease risk is associated with higher BMI, starting even as early as Class I obesity. Our study points to an urgent need for early interventions for people in all classes of obesity if we are to reduce the occurrence of these metabolic diseases.”

Corpodean was one of eight Pennington Biomedical researchers contributing to this paper. She recently presented the findings at ObesityWeek 2025 in Atlanta, the annual conference for obesity and metabolic health researchers.  

“While these individual associations of obesity and disease have been suggested, a key strength of this study is the collective examination of each of these cardiometabolic conditions in a single, nationally representative population,” noted Dr. Vance Albaugh, Assistant Professor and senior author who directed the project. 

Obesity increases the risks of diabetes, hypertension and heart disease, but most studies in this area consolidate all obesity cases together, rarely categorizing beyond a BMI greater than 40. These studies fail to capture the unique risks faced by those with more severe obesity. Adults with a BMI of 50 or more face dramatically higher odds of disease, pointing to a need for a clinical and research focus on treatment for individuals in this class.

"This research exemplifies what we're striving to achieve at Pennington Biomedical," said Dr. John Kirwan, Executive Director of Pennington Biomedical. "What's striking is how dramatically the risk of cardiometabolic and renal diseases escalates with each increasing level of obesity severity – it's a clear, stepwise progression. Our team at Pennington Biomedical and the Metamor Institute is bringing much-needed attention to individuals in higher BMI categories who haven't received adequate focus in clinical research. Understanding these distinctions is essential for developing more targeted, personalized approaches to treatment and prevention."

About the Pennington Biomedical Research Center

The Pennington Biomedical Research Center is at the forefront of medical discovery as it relates to understanding the triggers of obesity, diabetes, cardiovascular disease, cancer and dementia. Pennington Biomedical has the vision to lead the world in promoting nutrition, metabolic health and eliminating metabolic disease through scientific discoveries that create solutions from cells to society. The Center conducts basic, clinical, and population research, and is a campus in the LSU System.

The research enterprise at Pennington Biomedical includes over 600 employees within a network of 44 clinics and research laboratories, and 16 highly specialized core service facilities. Its scientists and physician/scientists are supported by research trainees, lab technicians, nurses, dietitians, and other support personnel. Pennington Biomedical is a globally recognized state-of-the-art research institution in Baton Rouge, Louisiana.

For more information, see www.pbrc.edu.


-30-

---

Journal

Obesity

DOI

10.1002/oby.70099 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Association of Obesity Severity With Cardiometabolic and Renal Disease Burden in the United States

Article Publication Date

18-Nov-2025

COI Statement

Dr. Schauer reports receiving research grants from Ethicon and Medtronic; receiving personal consulting fees or honoraria from GI Dynamics, Keyron, Persona, Mediflix, Metabolic Health International Ltd, Lilly, Heron, Novo Nordisk, and Klens; serving on scientific advisory boards for SE Healthcare Board of Directors, GI Dynamics, Keyron, Persona, and Mediflix; and having ownership interest in SE Healthcare LLC, Mediflix, and Metabolic Health International LTD. Dr. Albaugh reports receiving research grants from Ethicon and consulting fees from Novo Nordisk. The other authors declare no conflicts of interest.