Scientists cannot observe dark matter directly, so to “see” it, they look for signals that it has interacted with other matter by creating a visible photon. However, signals from dark matter are incredibly weak. If scientists can make a particle detector more receptive to these signals, they can increase the likelihood of discovery and decrease the time to get there. One way to do this is to stimulate the emission of photons.
Former University of Chicago graduate student Ankur Agrawal worked with scientists and engineers at Fermilab and the University of Chicago on his doctoral thesis research subject, “Stimulated emission of signal photons from dark matter waves.” Photo: Reidar Hahn, Fermilab
Scientists at the U.S. Department of Energy’s Fermi National Accelerator Laboratory and University of Chicago reported the ability to enhance the signals from dark matter waves by a factor of 2.78 using novel quantum techniques. This technology demonstrates how advances in quantum information science can be applied, not only to quantum computing applications, but also to new physics discoveries.
This exciting result was made possible by the DOE’s Quantum Information Science Enabled Discovery program, and the Heising-Simons Foundation. University of Chicago graduate student Ankur Agrawal conducted this research for his doctoral thesis supervised by Fermilab scientist Aaron Chou in collaboration with members of Professor David Schuster’s group at the University of Chicago. The results were recently published in Physical Review Letters.
For this experiment, the researchers first prepared a microwave cavity in a special quantum state. Then, they used superconducting quantum bits, or qubits, to increase the measurement sensitivity within that cavity so they could more easily detect any signals indicating the presence of dark matter.
“There are two ways to speed up an experiment; you can gather more signal or reduce noise,” said Schuster. “In this experiment we used a qubit to do both, preparing a quantum state of light that stimulates the creation of photons, and then using the qubit to probe the exact number of photons multiple times without destroying any to eliminate excess noise.”
The researchers prepared the microwave cavity using superconducting qubits in what is known as a Fock state. These quantum Fock states have a well-defined number of photons, and the higher the Fock state, the more likely it is that dark matter will interact. By preparing the cavity this way, as dark matter passes through the microwave cavity wall, the interaction will cause an extra photon produced by dark matter to be pumped into or removed from the cavity. The presence of one more or one less photon indicates that the photon was stimulated by dark matter.
“This experiment is a beautiful demonstration of one of the first things we learn in a quantum mechanics course about quantum states, and the results confirm what I learned,” said Agrawal.
The second part of the experiment involved engineering the interaction between the qubit and the cavity in such a way as to reduce the noise. At microwave frequencies, each photon has a tiny amount of energy which makes them very sensitive to the noise from the surrounding environment. To minimize the thermal photons from overwhelming the signal, researchers cool this cavity with a dilution refrigerator where the temperature is one-one-hundredth of a Kelvin—100 times colder than outer space.
Using superconducting qubits enabled them to engineer the interaction in such a way as to reduce the noise to extremely low levels, thereby increasing sensitivity.
“For this technique, we engineer the qubit-photon interaction so that the photon is not destroyed in the process of measurement,” said Akash Dixit, a scientist who was part of the research team at Fermilab. “This allows us to measure the same photon many times which reduces the influence of noise and increases our sensitivity to these rare events.”
Akash Dixit, a former University of Chicago postdoctoral researcher, participated in the project at Fermilab to stimulate photon emission. Photo: Ryan Postel, Fermilab
The overall technique is like pushing a child on a swing. If the child is not swinging, you need to push her much harder to get her moving; but if the swing is already swinging, you don’t have to push as hard.
“What we do is take the electromagnetic field in our microwave cavity or detector — the swing — and get it to start swinging so that it can more easily take pushes from the dark matter that’s passing by,” said Chou. “This process of stimulated emission is actually exactly how lasers work.”
Previous experiments started with a zero, or ground-state, field inside the cavity, the equivalent of the swing standing still.
“Scientists can use this technique to increase sensitivity to advance their search for dark matter, saving time and resources and to explore other mysteries of fundamental science,” said Agrawal.
Fermi National Accelerator Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
The addition of IBM as a new partner in the Superconducting Quantum Materials and Systems Center, a DOE National Quantum Information Science Research Center, hosted by Fermilab, has been approved by the U.S. Department of Energy Office of Science, Science Programs. As a major national and international research center, SQMS is dedicated to advancing critical quantum technologies, with a focus on superconducting quantum systems. IBM is an industry leader in developing superconducting quantum computing technology. This collaboration intends to leverage the strengths of these two organizations to address key hurdles in quantum computing, communication and large-scale deployment of superconducting quantum platforms.
“We welcome the addition of IBM to the SQMS collaboration, which brings together some of the world’s top experts in superconducting materials, devices and quantum systems. This collaboration aims to leverage our complementary technical strengths and shared goals to advance superconducting quantum systems for progressing toward a fault-tolerant quantum computer,” said Anna Grassellino, SQMS Center Director.
The SQMS Center brings together more than 30 partner institutions representing national labs, industry and academia. The diverse collaboration unites over 500 experts from around the world working together to bring transformational advances in quantum information science.
Pictured (left to right) at the SQMS Quantum Garage at Fermilab are: Akshay Murthy, associate scientist at Fermilab; Yao Lu, associate scientist at Fermilab; Jason Orcutt, principal research scientist at IBM; Tanay Roy, associate scientist at Fermilab; Andre Vallieres, PhD student at Northwestern University; Silvia Zorzetti, department head, quantum computing co-design and communication at Fermilab; Jacob Hanson-Flores, summer intern at Fermilab; Alessandro Reineri, PhD student at Illinois Institute of Technology; Joey Yaker, PhD student at Northwestern University. Photo: Dan Svoboda, Fermilab
As part of the collaboration, IBM intends to focus on five critical areas: large-scale cryogenics, superconducting qubit noise sources, quantum interconnects, quantum computing applications for fundamental physics and quantum workforce development.
“Fermilab and the SQMS Center are the ideal places to develop these key technologies and produce them at scale,” said Lia Merminga, Fermilab director. “We have decades of experience building large, complex superconducting cryogenic systems for accelerators and adopting advanced instrumentation to further our science mission. The advancement of quantum information science is a national priority, and Fermilab is deeply engaged in that progress.”
Large-scale cryogenics
SQMS and IBM intend to work together to advance technologies critical for scaling up quantum computers to large-scale data centers. SQMS is already proposing novel solutions for higher efficiency large-scale milliKelvin cryogenics at Fermilab. These developments in cryogenics will include the world’s largest dilution refrigerator to host 3D superconducting radiofrequency (SRF)-based quantum computing and sensing platforms, called Colossus. IBM will provide practical information and specifications to broaden the impact of Colossus. This includes developing a large-scale cooling system based on LHe/N2 plants, which would suit IBM’s future large-scale commercial quantum computing systems.
High-quality and high-density quantum interconnects
SQMS is designing and prototyping high-quality and high-density quantum interconnects based on 3D SRF platforms for quantum computing platforms being developed at Fermilab. These developments are also applicable to scaling up chip-based modular systems. Fermilab and IBM aim to explore the feasibility and usability of quantum links as part of a commercial quantum system with a focus on high-quality microwave cables.
Noise reduction in qubits and processors
As part of the SQMS Center, IBM and SQMS partners intend to work together to further the scientific understanding of mechanisms limiting the performance of superconducting qubits and developing practical schemes for the so-called “1/f flux noise” abatement.
Development of scientific applications of quantum computing systems
SQMS partners and IBM plan to advance the study of physics-based applications of quantum computing systems. For example, in condensed matter physics, researchers aim to explore the use of IBM’s utility-scale processors to support a quantum many-body dynamics simulation, whose complexity approaches a quantum advantage regime. For high-energy physics, partners will explore simulations of lattice quantum field theories.
Quantum workforce development programs
To attract and train the next generation of a diverse quantum workforce, SQMS established several successful workforce development programs, including the U.S. Quantum Information Science School shared with the other four National Quantum Information Science Research Centers (NQISRC) funded by DOE. IBM has a robust quantum education program that has enabled millions of learners worldwide and helped provide industry and domain expertise at Fortune 500 companies, universities, laboratories and startups within the IBM Quantum Network by providing tools to build their quantum workforce. SQMS and IBM plan to join forces to strengthen national quantum workforce development programs.
Colossus will offer 5 cubic meters of space and cool components to around 0.01K. Photo: Ryan Postel, Fermilab
“As we accelerate towards building a large-scale, fault-tolerant quantum computer, we need to solve and scale complex challenges such as efficient, large-scale refrigeration and high-density and low-loss quantum interconnects and advance our understanding of noise sources and how to reduce them,” said Jay Gambetta, IBM Fellow and Vice President, IBM Quantum. “The planned participation in the SQMS Center’s research is a pillar for progressing our roadmap towards large-scale quantum computing. Alongside the collaboration to break through quantum hardware barriers, IBM and Fermilab intend to work together to drive scientific applications of quantum computing and build a quantum-ready workforce.”
The start of the collaboration is pending final approval of a legal agreement between IBM and Fermi Research Alliance, LLC.
The Superconducting Quantum Materials and Systems Center at Fermilab is supported by the DOE Office of Science.
The Superconducting Quantum Materials and Systems Center is one of the five U.S. Department of Energy National Quantum Information Science Research Centers. Led by Fermi National Accelerator Laboratory, SQMS is a collaboration of more than 30 partner institutions — national labs, academia, and industry — working together to bring transformational advances in the field of quantum information science. The center leverages Fermilab’s expertise in building complex particle accelerators to engineer multiqubit quantum processor platforms based on state-of-the-art qubits and superconducting technologies. Working hand in hand with embedded industry partners, SQMS will build a quantum computer and new quantum sensors at Fermilab, which will open unprecedented computational opportunities. For more information, please visit sqmscenter.fnal.gov.
Fermi National Accelerator Laboratory is America’s premier national laboratory for particle physics research. A U.S. Department of Energy Office of Science laboratory, Fermilab is located near Chicago, Illinois, and operated under contract by the Fermi Research Alliance LLC. Visit Fermilab’s website at https://www.fnal.gov and follow us on Twitter @Fermilab.
Anna Grassellino, senior scientist at Fermi National Accelerator Laboratory and the director of the Superconducting Quantum Materials and Systems Center, was awarded the prestigious Marisa Bellisario Award on June 18, 2024.
Anna Grassellino receives the Marisa Bellisario Award, “Women who make the difference,” from Italian Minister of Foreign Affairs Antonio Tajani. Credit: Marisa Bellisario Foundation
Grassellino, originally from Marsala, Italy, has made significant contributions to the field of superconducting radiofrequency (SRF) technology, a critical technology in modern particle accelerators and quantum information science. She has led groundbreaking work in increasing the efficiency of SRF cavities and their use in several novel experiments, ranging from quantum computing to searching for new particles, which is at the core of the SQMS Center mission.
“I’m so honored to be recognized with this award among extraordinary women who have distinguished themselves and have made important contributions in many fields from science to economy to entrepreneurship to sports and so much more,” said Grassellino. “I hope to serve as a role model for young women who aspire to have a career in STEM.”
The 10 award recipients met with Italian President Sergio Mattarella and Bellisario Foundation President Lella Golfo at Palazzo Quirinale. Later that evening, a formal ceremony was held in Rome’s historic Colosseum where Grassellino received the award from Italian Minister of Foreign Affairs Antonio Tajani.
The recipients of the Marisa Bellisario Award gather for a photo at a meeting at Palazzo Quirinale with Italian President Sergio Mattarella. Credit: Marisa Bellisario Foundation
The Bellisario award recognized Grassellino’s outstanding achievements and her influence as a role model for women in science and technology. The award citation read by Minister Tajani stated: “Anna Grassellino receives the Bellisario Award for the extraordinary talent, determination and courage that have earned her the international leadership in research, in technologies that will open new scientific horizons. She is an ambassador of the Italian genius in the world and source of inspiration for all girls who aspire to have a STEM career.”
The Marisa Bellisario Award is one of Italy’s most prestigious honors dedicated to women who have excelled in various professional, social, cultural and scientific fields. The award was established in 1989 in memory of Marisa Bellisario, one of Italy’s first successful female managers. It celebrates female excellence and promotes the role of women in the workplace and society.
Italian President Sergio Mattarella congratulates Anna Grassellino for receiving the international award from the Marisa Bellisario Foundation. Credit: Marisa Bellisario Foundation
“This is an impressive award and I extend my most sincere congratulations to Anna for receiving this recognition,” said Lia Merminga, Fermilab Director. “Anna is a wonderful ambassador for the mission of Fermilab. The lab community and I are very proud of her.”
More information about the Marisa Bellisario Foundation and its mission can be found here.