Neutrons, when plucked from the nucleus of atoms, become unstable and decay after some time. Physicists know that these unstable neutrons die after about 14 minutes, but they cannot pinpoint the exact seconds in which the neutrons last, even as today’s experiments are at their most precise. 

This problem, known as the neutron lifetime anomaly, arises because two different but equally rigorous experimental methods – the beam method and the bottle method – produce different results. A popular reason is that some undiscovered phenomenon might be at play.

But Dr. Denny Lane Sombillo of the UP Diliman College of Science National Institute of Physics (UPD-CS NIP) thinks the explanation may lie in how time behaves at a quantum level. “If this [theory] is correct,” he said, “we don’t need to modify the known physics and simply focus on the nature of time in quantum mechanics.”

Dr. Sombillo’s theory involves a separate problem called the quantum time of arrival (QTOA) problem. His theory is built upon the works of Dr. Eric Galapon of UPD-CS NIP. By employing Einstein’s concept of causality in Dr. Galapon’s work, Dr. Sombillo provides an intuitive picture of the quantum time of arrival problem, one that can be used to explain other mysteries such as the neutron lifetime anomaly.

Time of Arrival in Classical vs. Quantum Mechanics

In classical mechanics, a car traveling at 40 kilometers per hour will arrive at the destination 40 kilometers away in exactly one hour. So long as the speed of the car and the distance to the destination do not change, we can be sure that the car’s time of arrival will always be one hour.

A different story emerges in quantum mechanics. An atom traveling at some speed will reach its destination – say, a detector – after some time. However, a weird quirk of an atom is that we can prepare its exact position or exact speed, but not both at the same time. That is, we can prepare it with an exact speed, but we cannot set how far away it is from the detector, and vice-versa. As a result, we cannot be sure of the atom’s time of arrival; we can only know the probability of it arriving after a certain time.

This feature called the Heisenberg uncertainty principle, owes its weirdness to the duality of atoms as both a wave and a particle. Naturally, atoms are clouds of probabilities with no definite properties, much like the ambiguity of a wave. When measured or prepared, however, atoms instantaneously acquire exact properties, much like the distinctness of a particle.

Dr. Galapon’s theory on QTOA posits that right after the atom is prepared, it collapses into a specific type of wave. After some time, this wave will evolve and turn into a particle. This process is aptly named the Galapon collapse mechanism (GCM).

Employing Causality

However, Dr. Sombillo noticed that the theory allows for a situation where the atom instantaneously arrives at the detector. That is, the atom can “teleport” to the detector, rendering no time to travel, which is physically impossible. This also violates the concept of causality, which states that one event (a cause) must first happen before another event (an effect).

“You can think of causality as the proper ordering of events,” Dr. Sombillo explained. In the traveling atom, for example, the proper order of events would be that the atom must be prepared first (a cause) before appearing at the detector (an effect). That is, the atom should not be detected by the detector if it has not yet been prepared.

Dr. Galapon’s theory allows for the reversed ordering of events where the detection of the atom precedes its preparation.  “Intuitively, this reversed ordering should not be in the theory, but it is not easy to identify this loophole using mathematics alone,” Dr. Sombillo said. “One needs to evaluate the physical implications of the formalism.”

By employing causality, Dr. Sombillo and his collaborator, Dr. Neris Sombillo of Ateneo de Manila University, were able to fix the issue. “We found that the instantaneous arrival time can be removed if we impose causality in the formulation of the time of arrival operator theory,” he said. “Even if we remove the causality-violating part, the quantum correction to time remains.” Their improved formulations can now be used to explain physical phenomena such as the neutron lifetime anomaly.

Neutron Lifetime Anomaly

When an unstable neutron dies, it changes into a proton, emitting an electron and antineutrino. But exactly how long before this process happens is still unknown. The beam experiment suggests that the unstable neutron lasts an average of 14 minutes and 48 seconds, while the bottle experiment suggests 14 minutes and 39 seconds – a nine-second difference.

Dr. Sombillo believes that the difference comes from how the neutrons are initially prepared, which would have affected their lifetime. Just like in the quantum time of arrival problem where the atom’s particle-like state affects how it will evolve into a wave, the neutron’s initial state affects how it will decay.

The beam and bottle experiment, he theorizes, sets the neutrons with dissimilar quantum characteristics. Plugging these values into his equations on quantum time of arrival would result in different neutron lifetimes, accounting for the discrepancy in the experiments.

Now published in Physics Letters A, their paper is the first to merge causality and the quantum time of arrival problem, as well as use it to explain the neutron lifetime anomaly. “Our work is the only proposal that presents the anomaly as a quantum correction to a time observable,” Dr. Sombillo said.  “The paper laid the foundation for future work on the neutron lifetime anomaly using the theory of quantum arrival.”

While their work is still at its preliminary stage, he said that they intend to pursue a more thorough investigation of the quantum time theory in the future. Before transitioning as a nuclear physicist, Dr. Sombillo was part of the quantum time operator research group of UPD-CS NIP. He later learned about the neutron lifetime anomaly and how it might relate to the quantum time of arrival problem after his transition.

For interview requests and other concerns, please contact media@science.upd.edu.ph.

References:

Sombillo, D. L. B., & Sombillo, N. I. (December 5, 2023). Formulation of causality-preserving quantum time of arrival theory. Physics Letters A, 490, 129205. https://doi.org/10.1016/j.physleta.2023.129205

Galapon, E. A. (2008). Theory of quantum arrival and spatial wave function collapse on the appearance of particle. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 465(2101), 71–86. https://doi.org/10.1098/rspa.2008.0278 

Wietfeldt, F. E., & Greene, G. L. (2011). Colloquium: The neutron lifetime. Reviews of Modern Physics, 83(4), 1173–1192. https://doi.org/10.1103/revmodphys.83.1173

Students of the UP Diliman College of Science (UPD-CS) and the Republic Polytechnic in Singapore (RP) immersed themselves in the month-long Temasek Foundation International Specialists’ Community Action and Leadership Exchange (TFI SCALE) Programme, the first half taking place in Singapore on September 6 to 19, 2023, and the second half in the Philippines last March 31 to April 8, 2024.

The TFI SCALE Programme aims to promote cultural, cognitive, social, and emotional engagements among Southeast Asian youths. In the 9th iteration of the program, students from the National Institute of Geological Sciences (UPD-CS NIGS), Institute of Biology (UPD-CS IB), and National Institute of Molecular Biology and Biotechnology (UPD-CS NIMBB) collaborated with students from RP’s School of Applied Sciences.

As part of the program in the Philippines, the exchange students visited Mt. Pinatubo, the Las Piñas-Parañaque Wetland Park (LPPWP), and the Parañaque Science High School (ParSci) to explore the country’s climate, biodiversity, research, and sustainability issues.

The participants were divided into three groups: the microplastics group which examined the presence of microplastics in Manila Bay, the coliform group which investigated human and animal waste in the bay, and the mangrove cleanup trash segregation group which surveyed various types of trash found in the protected mangrove area of LPPWP.

Dr. Cristine Villagonzalo and Dr. Reynaldo Garcia from the UP Diliman College of Science (UPD-CS) received the prestigious Achievement Award from the National Research Council of the Philippines (NRCP) in the recently held Annual Scientific Conference and 91st General Membership Assembly last March 12, 2024.

Dr. Villagonzalo of the UPD-CS National Institute of Physics (UPD-CS NIP) was lauded for her contributions to Physics, and Dr. Garcia of the UPD-CS National Institute of Molecular Biology and Biotechnology (UPD-CS NIMBB) for his contributions to the field of Medical Sciences.

Dr. Villagonzalo served as the President of the NRCP Governing board from 2022 to 2023. She is a Professor and the Deputy Director for Academic Affairs at NIP and the Project Leader of the International Year of Basic Sciences for Sustainable Development (IYBSSD) Philippines. Dr. Villagonzalo received her doctorate of natural sciences at Chemnitz University of Technology in Germany. She is currently working on a research project to integrate a quantum mechanics principle called the perturbation theory in a quantum circuit.

Dr. Garcia founded the Disease Molecular Biology and Epigenetics Laboratory (DMBEL) at NIMBB in 2011. He and his team played a crucial role in detecting and preventing the spread of COVID-19 during the pandemic. Dr. Garcia received his doctorate in Biochemistry and Molecular Biology at the Australian National University and is currently a Professor at NIMBB. He is currently investigating how specific mutations in colon cancer cells affect their resistance to treatments, and how these mutated cells divide, migrate, and survive.

The NRCP started awarding the Achievement Award in 1979 to those who have significantly contributed to the research and development of natural sciences, health sciences, engineering, industry, social sciences, and humanities in the Philippines.

Aside from Dr. Villagonzalo and Dr. Garcia, three professors from UP Los Baños also received the Achievement Awards, namely Dr. Inocencio Buot Jr. for his contributions to Biological Sciences, Dr. Maria Ana Quimbo for Social Sciences, and Dr. Remil Galay for Veterinary Medicine.

The UPD Department of Chemical Engineering was awarded the 2023 NRCP Outstanding Institution Award. It joins the ranks of UPD-CS institutes that have received the award, namely NIP, Marine Science Institute (MSI), and Natural Sciences Research Institute DNA Analysis Laboratory (NSRI-DAL).

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Pamela Louise Tolentino of UP Diliman College of Science National Institute of Geological Sciences (UPD-CS NIGS) and CS Dean Giovanni Tapang are among the Filipino scientists highlighted by the UK in their decadal recap of joint scientific achievements with the Philippines.

Since 2014, Filipino scientists have been collaborating with UK scientists through the scientific partnership between the two countries. In 2016, the Newton Agham Fund was launched, aimed at providing £3 million (about ₱180 million) of funds for key research projects in health and life sciences, environmental resilience, and energy security.

Tolentino is one of the lead investigators in their project examining where rivers flow and how they change landscapes. By understanding the geomorphological processes behind river systems, their work provides evidence-based solutions for a more effective flood risk assessment and planning. Tolentino and colleagues’ work is under the “Understanding the Impacts of Hydrometeorological Hazards in Southeast Asia Programme” and is funded through the Newton Agham Fund.

In 2016, Dean Tapang was a Leaders in Innovation Fellow, a program that trains and mentors scientists in bringing their inventions to the market. Last year, he spearheaded the commercialization of the Versatile Instrumentation System for Science Education and Research (VISSER), a portable learning device that allows students to conduct 120 experiments in chemistry, biology, environmental science, and physics. At the end of the year, the company distributed 43 VISSER units and generated ₱3.4 million in total revenue. Read the VISSER press release here.

“Every project should have collaboration and inclusion at its core to have impacts that last way beyond its lifetime,” said Tolentino in UK’s Science Snapshot. “I honestly believe that more than the outputs such as methods and data developed from the project, it is truly the conversations where the common goal of providing a better future for everyone that will drive the changes.”

To express interest in continuing the partnership, the UK and the Philippines held the first Joint Committee Meeting (JCM) at The Manila Peninsula Makati City on February 22, 2024. The JCM would now be held every two years to bolster cooperation between both parties.

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Much like carbonated drinks are water infused with carbon dioxide, gas hydrates are ice mostly infused with methane, a natural gas used as fuel. Gas hydrates are ice-like substances that usually only form beneath the seafloor, where the pressure is high and the temperature is just below the water’s freezing point of 0°C.

Elisha Jane Maglalang, Dr. Leo Armada, Madeleine Santos, Karla May Sayen, and Dr. Carla Dimalanta of the UP Diliman College of Science National Institute of Geological Sciences (UPD-CS NIGS) discovered that gas hydrates may be abundant in the Manila Trench, west of Luzon. Their study is the first to investigate these substances in Philippine trenches, pioneering gas hydrate research in the country.

Because gas hydrates contain huge amounts of carbon and methane, they can be a great alternative energy source. “The western Philippines has vast potential for this unconventional energy resource,” the researchers said. They discovered that a total area of around 15,400 square kilometers in the Manila Trench, or about the size of Palawan, could contain gas hydrates. They estimate these substances might be around 200 to 500 meters below the seafloor.

However, gas hydrates can be a geologic and environmental threat. Because gas hydrates are unstable solids, they will dissociate and melt when the conditions in which they form change, usually during earthquakes. Worryingly, the Manila Trench is an active margin, responsible for numerous earthquakes in Western Luzon. When gas hydrates melt, it will agitate the seafloor, possibly triggering submarine landslides and tsunamis.

Moreover, methane can harm the environment when released into the atmosphere. Methane is a potent greenhouse gas that contributes to global warming, and just one cubic-meter block of gas hydrate contains as many as 160 cubic-meter blocks of methane in its gas form. This is equivalent to 14% of an average Filipino’s methane emission in 2021.

“Therefore, it is essential to determine the distribution and stability conditions of gas hydrates offshore of the Philippines,” the researchers emphasized.

To determine their location without drilling through the seafloor, scientists rely on sound waves. Similar to how a pond reflects sunlight, gas-bearing substances like gas hydrates reflect sound waves. These seismic reflections, called bottom-simulating reflectors (BSRs), indicate where gas hydrates might be present. By analyzing existing seismic data in the Manila Trench, the UP geologists were able to map out BSRs and, consequently, deduce possible locations of gas hydrates in the region.