Well, the first point to make is that it would be unusual to find someone with a quantum scientist title or some academic degree in “quantum science.” Since quantum science has such wide applicability, it’s used by lots of different fields of science, such as chemistry, physics, and many types of engineering. People usually get academic degrees in these types of fields, but are learning some quantum science while doing so. If a person gets a degree in chemistry and ends up using a lot of quantum mechanics in their work, they might be identified as a “quantum chemist.”
So, are there also “quantum physicists” and “quantum engineers”?
You won’t usually encounter people with these titles, even though quantum understanding is essential to both physics and engineering. In the case of physics, most physicists use quantum science in their work, some sparsely and some intensively – this is true for subfields ranging from astronomy and astrophysics to condensed matter physics to particle physics. Engineering disciplines where you’ll frequently encounter quantum science include electrical engineering, materials science, chemical engineering, and mechanical engineering.
And are there different subfields of chemistry that use quantum mechanics besides quantum chemistry?
Absolutely. Almost all chemists are concerned with the making and breaking of chemical bonds between atoms, and, among many other things, quantum mechanics underlies the rules of how bonds are made and broken. Some chemists will want to spend a lot of time understanding the quantum nature of bonds as part of their work, while others may not feel the need to. Someone who does biochemistry is less likely to spend time thinking about the things they work on in terms of quantum mechanics, while someone who does physical chemistry is more likely to.
Besides Chemistry, Physics, and Engineering, are there other scientific fields where people learn quantum science?
Yes, people in other physical sciences, like earth science and materials science, can require a quantum understanding of some things. As quantum mechanics can be viewed as a general theory of information, there’s increasing interest in it in computer science as well. This interest is also related to the development of new technologies like quantum computers, which is also an area where you’re starting to see people who identify as quantum engineers. There are also an increasing number of examples of people looking into whether quantum concepts are useful for biological systems.
I gather then that while there are few people who identify as quantum scientists, there are a lot of different types of scientists who use quantum science.
Yes! This is probably not that surprising since quantum mechanics is such a wide-ranging theory and is understood to be the ground rules for the physical world. You would expect that a theory that powerful would be useful for many different types of science. One useful thing about learning more quantum science is that it is knowledge that you can take with you if you go from one field to another.
Written by Paul Cadden-Zimansky, Associate Professor of Physics at Bard College and a Global Coordinator of IYQ.
IYQ mascot, Quinnie, was created by Jorge Cham, aka PHD Comics, in collaboration with Physics Magazine. All rights reserved.
Interview with Dr. Alexia Auffèves, French physicist, pioneer of quantum energetics, and co-founder of the Quantum Energy Initiative (QEI).
Quantum physics has been the star of the tech world for almost a century now. However, a second quantum revolution is quietly emerging, shaking up the very foundations of how computers work at every level, from the principles behind the information itself and how the machines physically process it, to the algorithms. These new quantum technologies promise exceptionally faster computations and more secure communications.
As governments and industries invest heavily in quantum systems, it’s time to think about how we build and use them responsibly. That means not just focusing on what they can do but also on how much energy they use to accomplish tasks. Environmental and societal challenges recognized nowadays impose new constraints that were not obvious when classical computers first emerged. Early signs from quantum processors show lower energy consumption compared to traditional machines, but we don’t fully understand why and whether this advantage will persist as they scale.
In a seminal paper published on Physics Review X Quantum, in 2022, physicist Dr. Alexia Auffèves, First Class Research Director at CNRS in France, head of the International Research Lab MajuLab and invited Professor at the Centre for Quantum Technologies of Singapore argues that “a strong link between fundamental research and engineering is necessary to establish quantitative connections between quantum-level computing performance and energy consumption at the macroscopic, full-stack level.” In the framework of the International Year of Quantum Science and Technology, we had a conversation with Dr. Alexia Auffèves about her work as a pioneer of quantum energetics and as a co-founder and leader of the Quantum Energy Initiative (QEI) —an interdisciplinary effort that brings together experts in quantum physics, thermodynamics and energetics, computer science, and engineering aiming to understand how quantum technologies use energy from the ground up.
“I have been working in quantum thermodynamics for twelve years now, and at the beginning the impact of this research for quantum technologies was not easy to spot. The community of quantum thermodynamics was barely involved when the big takeoff in quantum technologies took place. I was part of the quantum thermodynamics community, but also had a vision of what was going on with quantum technologies because of my past as an experimentalist, and because I was running the Grenoble center for quantum technologies. So, I saw that there was clearly a gap to bridge between the two communities,” Alexia says.
Drawing lessons both from the history of classical computing and the recent developments in artificial intelligence, Auffèves reminds us that energy efficiency does not happen by accident: If you don’t search for it, you won’t find it. In the case of quantum computing, it may require decades of refinement, from understanding fundamental principles connecting energy cost and performance, to designing chips that balance performance with power consumption.
Creating an international research community to understand the energetic footprint of emerging quantum technologies
Motivated by the timeliness and relevancy of addressing the energy cost of quantum technologies, Alexia, her colleagues Robert Whitney and Janine Splettstoesser, and consultant and author Olivier Ezratty co-founded the Quantum Energy Initiative (QEI) in 2022.
That means establishing ways to measure energy efficiency in quantum devices, setting benchmarks, and identifying how to reduce energy consumption across different quantum platforms and computing paradigms. Quantum computing would be addressed first, but communication, and sensing, the two other so-called pillars of quantum technologies, would be investigated as well. The QEI team aims to define what “energy quantum advantage” really means in scientific terms and use that knowledge to guide smart design choices as quantum systems develop.
“The QEI is one of the first attempts to develop innovation in a finite world. In the past, innovators used to invest lots of money, hoping that something would come out. Now, we have to take into account the fact that the physical resources, especially energy, are finite. In that sense, quantum computing is growing in very, very different conditions than its older sister, classical computing, when there was oil all over the place, and so you could develop technologies presuming that we have infinite resources.”
But launching such initiatives, where fundamental science and emerging technologies intersect, also means navigating the influence of industry sectors, which often seek to align themselves with the prevailing ethical narratives of the time.
“When you launch an initiative like this, you are not really aware of the kind of forces it is going to trigger, especially nowadays, where there is a lot of quantum hype. If you mix this hype with the word “energy”, then it can quickly become unbearable. The QEI is not a greenwashing company. We are here precisely to prevent greenwashing. We are here to provide the community with objective scientific figures of merit so that sentences like: “Oh! My quantum computer will compute with less energy.” can be checked, and the energy efficiency of this very computer can even be compared to a fundamental bound and improved over time.
Can we build a theory that captures the quantum and the classical altogether?
To understand the true energy cost of quantum computing, we must look beyond hardware specifications and operational efficiency. At the heart of the challenge lies a much deeper, more conceptual problem: how to capture the quantum and classical worlds within a single physical model. This isn’t just a technical hurdle—it’s the oldest and still open problem of quantum physics, known as the measurement problem.
Any computation—whether classical or quantum—can be broken down into three stages: input, processing, and output. In quantum computing, both the input and the computational process involve inherently quantum phenomena such as superposition and entanglement. However, obtaining the result (the output) requires a measurement, a process that plays a central role in our understanding of quantum mechanics. Scientists remain puzzled by what exactly occurs during measurement, when quantum properties are seemingly lost as the quantum system interacts with the classical apparatus used to observe it.
“If you think about a quantum computer, while the computation is being performed, we deal with Schrödinger’s cat states, i.e. superpositions of states of “macroscopic” systems – here, data registers made of large numbers of qubits. So, there you have Schrödinger’s cat states in a box (a cryostat, for instance) that you are trying to control from the external [classical] world. And my feeling is that the truly fundamental energy cost of quantum computing is actually the cost of the box surrounding the Schrödinger’s cat.
Answering that question is hardware-independent and would also be a way to solve one of the biggest open questions of quantum physics: can we build a theory capturing the quantum and the classical altogether?
Nowadays, this question belongs to the field of quantum foundations, which is largely decoupled from quantum technologies where ‘Shut up and calculate’ [the answer usually given by engineers and academics to people wondering on the philosophical meaning of quantum theory] has been proven an efficient strategy; However, if you really want to calculate minimum energy costs and get a universal framework to benchmark all possible quantum platforms, solving that fundamental problem is highly relevant. This is a beautiful example of how the answer to foundational issues can be triggered by technological questions, just like the thermodynamic arrow of time came out from the optimization of heat engines,” Dr. Auffèves enthusiastically explains.
Quantum energetics at the forefront of the fundamentals of quantum physics itself
Peeling back the layers of abstraction to understand what’s really happening inside a quantum computer is foundational to asking deep questions about the nature of energy, noise, and computation at the quantum level. Alexia reflects on how her investigation offers a window into that philosophical and scientific inquiry, one that challenges us to rethink what “energy cost” means in the quantum world.
This is research driven by curiosity, not utility, by the desire to grasp what quantum energetics truly means at its core.
“My research is about understanding the fundamental mechanisms ruling flows of energy, entropy and information at the quantum level, and how these behaviors scale up to the macroscopic level. This research line dubbed quantum energetics is young, fundamental and it has an intrinsic value, out of any technological considerations. It is very important to underline that the QEI does not only promote a technologically-driven research. We also foster this fundamental core of quantum energetics. It is curiosity-driven and has triggered a number of exciting new questions lately, like measurement-powered engines where looking at a quantum system is enough to put it in motion!”
Dr. Alexia Auffèves kindly explains what quantum energetics is.
“It is inspired by classical thermodynamics, whose first motivation is to turn ‘messy energy’ (heat) from hot baths into a useful, controllable one (work). That is called a heat engine, and thermodynamics tells us what is its maximal efficiency, which is a fundamental bound. A second motivation is to reverse natural heat flows, which has a work cost: this is called a fridge, and it also has a fundamental bound. Now, what plays the role of the heat in quantum physics is quantum noise (like decoherence), which comes from the coupling to baths which do not necessarily have a well-defined temperature. This is why I talk about quantum energetics and not quantum thermodynamics (where temperatures play a central role). One of the purposes of the field is to derive quantum fundamental bounds: find the minimum energy cost for any kind of quantum process, for any kind of quantum noise. We want to relate irreversibility and energy waste in the quantum realm, where there is no temperature in the picture. This line of investigation is all about understanding the fundamentals of quantum physics with energetic and entropic probes.”
While much of quantum research today is driven by the race to innovate and commercialize, there remains a quieter, deeper pursuit—one that asks foundational questions about the nature of energy, noise, and irreversibility at the quantum level.
In a world increasingly shaped by energy concerns and climate imperatives, amazing women in science, such as Dr. Alexia Auffèves and the QEI, offer a roadmap for responsible innovation while pioneering fundamental research in quantum mechanics. It’s time to power the quantum future, with precision, purpose, and sustainability.
The quantum future doesn’t have to repeat the mistakes of the digital past. It can be better—if we start now.
We’ve talked about what quantum means, but what does “quantum mechanics” mean?
Quantum mechanics is a very general set of rules governing the physical world that was developed starting in 1925. The year 2025 was chosen as the International Year of Quantum Science and Technology because it marks 100 years of quantum mechanics. We’ve talked elsewhere about what quantum means; the mechanics part refers to a systematic set of rules that can be widely applied to describe how things move and change.
Do “quantum mechanics” and “quantum theory” mean the same thing?
These terms are often used interchangeably, but a conceptual and historical distinction can be made between them. Historians usually trace the beginning of quantum theory to the year 1900. This is the first time a quantum hypothesis – in this case, that energy came in countable pieces – was introduced in trying to understand a physical phenomenon. It became clear this was a useful hypothesis, but there was disagreement at the time about what its physical significance was. In the period from 1900 to 1925, other physical phenomena were explained using this and other quantum hypotheses. This was a period of quantum theory, sometimes now called the “old quantum theory,” but it was before there was quantum mechanics.
Then what changed to go from quantum theory to quantum mechanics?
In the 1900-1925 period, there was no consistency in how and when to apply these quantum hypotheses to explain experiments and make predictions. Sometimes they seemed to work spectacularly well, which gave many people confidence that there must be something to the idea. But many other times, scientists tried to use these hypotheses to model or predict things, and the model didn’t make any sense, or the predictions were wrong. The point is that there was no systematic way of applying quantum theory ideas to different physical systems. A systematic method would be a “mechanics.”
And this systematic method was developed in 1925?
The groundwork for it, yes. The basic framework and some general sets of principles to follow took a few years to sort out in order to be able to apply them systematically to a wide range of problems. People are even now still working to revise and extend this framework, but many of the core pieces of quantum mechanics were put in place in 1925. The term “quantum mechanics” started to be widely used in the 1920s to describe these systematic rules. It was also a phrase that distinguished this new mechanics from what’s now called “classical mechanics.”
What is “classical mechanics”?
Classical mechanics, or sometimes just “mechanics,” is the framework for describing the motion of massive objects that was initially developed in the 17th century. This framework is a set of general rules that can be used to describe how planets orbit the sun or the rate at which a dropped object falls to the ground.
These would be ideas like “to every action, there is an equal and opposite reaction” and other rules of motion?
Yes, exactly. The rules of classical mechanics are still very useful and often easier to use than those of quantum mechanics, but quantum mechanics is an even broader theory that, in many scientists’ assessments, supersedes the rules of classical mechanics. One way to put it is that by the end of the 19th century, scientists thought they had a good, systematic theory for how matter moved around – that’s classical mechanics – and a good, systematic theory for how light worked – this is the electromagnetic wave description of light. However, there were a number of puzzles in trying to understand how light and matter interacted with each other. In the period from 1900-1925, some of these puzzles seemed to be solved using quantum ideas, but there was no systematic understanding of how light and matter interacted in all cases.
And quantum mechanics provided a systematic way for understanding how light and matter interact?
Not only did quantum mechanics provide a full description of how light and matter interact, but in doing so it dramatically revised our understanding of light and matter and the rules governing each of them. The earlier “classical” rules governing matter and light were revealed to be only approximations of a richer, quantum description of matter, light, and their interactions.
Written by Paul Cadden-Zimansky, Associate Professor of Physics at Bard College and a Global Coordinator of IYQ.
IYQ mascot, Quinnie, was created by Jorge Cham, aka PHD Comics, in collaboration with Physics Magazine. All rights reserved.
Accurate characterization of the environmental effects on a quantum system remains a fundamental challenge in the theory of open quantum systems. In this talk, I will introduce the purified pseudomode approach developed by us recently. This method allows for efficient modeling and numerically exact simulation of general linear-Gaussian baths. Extensions of this method to model bath input-output and nonlinear system-bath interactions will also be discussed.
Quantum Key Distribution (QKD) has emerged as a revolutionary technology for secure communication, leveraging the principles of quantum mechanics to ensure unbreakable encryption. Recent advancements in space-based QKD have enabled global-scale secure communication by utilizing microsatellites as cost-effective and efficient platforms for key distribution. Here, we will be presenting our recent groundbreaking results on the first quantum satellite link implemented in the Southern Hemisphere and the longest intercontinental ultra-secure quantum satellite link of 12,900 km between South Africa and China.
Quantum biology is an exciting field of research with a pronounced interdisciplinary focus. The aim of the mini-school is to first address the miscommunications that might arise from this interdisciplinarity. The first lecture will begin with a short history of quantum biology before clarifying some of the important concepts in the field, from the point of view of both physics and biology. The second lecture will build on this by reviewing the different biological contexts in which quantum effects may play a role, which include photosynthesis, enzyme catalysis, DNA mutation, receptor binding, microtubule and mitochondrial function, magnetoreception, regulation of the production of ROS, calcium ion storage and release, and potentially, consciousness. The final lectures will focus on two different worked examples: a spin-based model of entangled neural activation by calcium phosphate molecules and a vibration-assisted tunnelling model for the binding of the SARS-CoV-2 spike protein to its host cell.
In celebration of the International Year of Quantum Science and Technology, the Harvard Quantum Initiative invites students ages 14–19 to participate in an exciting global competition!
Create and submit a short video that explores a topic in quantum science—whether it’s quantum computing, entanglement, superposition, or any concept that inspires you. This is your chance to showcase your scientific insight, creativity, and passion for discovery.
Selected winners will receive an exclusive opportunity to visit Harvard’s cutting-edge quantum research facilities and meet world-class scientists.
Quantum technology took the stage in Berlin on April 14. The highlight was the ceremonial return of the QuanTour light source to Urania, – a symbolic conclusion to a year-long journey through European research institutions. The QuanTour linked laboratories and universities across Europe as a precursor to this year’s International Year of Quantum Science and Technology.
“With the QuanTour, we wanted to set an example for networking, transparency and enthusiasm for quantum technology,” say the initiators, Doris Reiter and Tobias Heindel, who had the idea for the project two years ago. “Due to the great interest, the QuanTour light source will make one more stop in Turkey before being passed on to the Physikalisch-Technische-Bundesanstalt.”
Measuring the same quantum light source more than a dozen times in different laboratories is a unique experiment and an important step toward establishing standards for quantum technologies. At the same time, the QuanTour made quantum research visible to the public across Europe: researchers gave insights into the physics laboratories and their everyday life in science via Instagram and in a podcast.
In addition to the return of the light source, the World Quantum Day event offered a varied program with numerous interactive experiments, workshops, and a hands-on exhibition. During the workshop on quantum cryptography, students could playfully try out for themselves how a secret key is transmitted in the form of a random bit sequence using individual photons, and whether this was intercepted. Another workshop illustrated quantized conductance. With experimental skill, participants were able to observe quantum jumps in the conductance of gold wire using an oscilloscope by carefully pulling two gold wires apart.
In the hands-on exhibition, quantum phenomena such as superposition and entanglement were made accessible in a playful way, for example with the game Quantum Tic-Tac-Toe by the Junge Tüftler:innen or the artwork Quantum Jungle, which visualized the Schrödinger equation. The analogue Paul Trap by Q-Bus demanded skill in handling an ion trap experiment made of wood. The program was complemented by the touring exhibition Rethinking Physics, which highlighted the role of women in science. The booths of Leap, AQLS, Berlin Partner, BTU, and The Science Talk provided information about the multifaceted quantum landscape in Berlin.
The highlight of the evening was a Quantum Science Slam: five young researchers presented their scientific work in a creative and easy-to-understand way, from molecular films and stardust quantum computers to motion-dependent quantum emotions. Science journalist and physicist Sabrina Patsch, who humorously explained quantum entanglement using the fictional animals Quaninchen and Queerschweinchen, won the slam.
UNESCO and IUPAP are launching a new online colloquium series to explore how physics can drive positive change for society. This year’s theme: Quantum Science and Technology, aligned with the International Year of Quantum Science and Technology (IYQ 2025).
We are honored to open the series with Prof. Anne L’Huillier, 2023 Nobel Laureate in Physics, whose groundbreaking work in attosecond science reshaped our understanding of electron dynamics.
She will speak on: – Attosecond light pulses in quantum science – Her journey as a woman scientist in a frontier field
This interactive event will spark dialogue across disciplines and regions — from fundamental science to real-world impact.
