"Imagine Victorian London with skies full of airships and steam-powered robots filling the streets, interacting with people in top hats and petticoats. This kind of retrofuturistic blend defines the fantasy world of steampunk, a genre that spans literature, film, and more. Theoretical physicist Nicole Yunger Halpern believes her field, quantum thermodynamics, is the real-world equivalent of steampunk. Yunger Halpern explains, 'In steampunk, there’s this odd combination of an old-fashioned setting and futuristic technology. That’s exactly what we do in quantum thermodynamics"
"Thermodynamics, which emerged in the 1800s during the Industrial Revolution, explores the physics of heat, work, and energy. This field grew out of efforts to understand steam engines. In contrast, quantum physics focuses on phenomena at the atomic and subatomic levels, driving technologies like quantum computers.
In the past, some physicists doubted the idea of quantum thermodynamics, seeing it as contradictory. 'They thought of it as an oxymoron,' says Yunger Halpern. However, the two concepts are now converging in the form of quantum engines and other small-scale devices. Researchers in quantum thermodynamics are working to create the tools that describe heat, work, cooling, and efficiency in quantum systems, as well as to explore the limits of quantum devices. Yunger Halpern, a physicist at the National Institute of Standards and Technology, is a leader in this area.
'She has a vision, and she follows it,' says MIT physicist Aram Harrow. 'She also excels at inspiring others to join her.'
A significant contribution of Yunger Halpern's work is investigating the implications of Heisenberg’s uncertainty principle in thermodynamics. For instance, consider a cup of hot tea. Thermodynamics explains how heat and evaporating water molecules are exchanged between the tea and its environment, with energy and water conserved. But in quantum systems, quantities like energy and momentum may not be compatible, meaning they can’t be measured simultaneously.
Yunger Halpern's research explores how this incompatibility affects systems at the quantum level. For decades, few considered what happens when incompatible quantities are exchanged, but it turns out that incompatibility can alter system behavior. For example, incompatibility can reduce the amount of entropy (or disorder) created in such exchanges, potentially limiting a system’s experience of the 'arrow of time'—the concept that time moves forward due to increasing entropy.
Quantum thermodynamics has also led to exciting lab experiments. For instance, a single atom can function as a quantum engine that converts heat into work. Yunger Halpern now aims to apply quantum thermodynamics in practical autonomous quantum machines. These devices would operate independently, without constant human intervention, unlike traditional quantum devices.
Yunger Halpern and her team have made strides in this direction with the development of an autonomous quantum refrigerator that can cool a quantum bit. In a 2023 paper, they outlined the criteria for building autonomous quantum machines, including maintaining structural integrity and ensuring the output is worth the energy required to run them. Quantum physicist Marcus Huber, who worked with Yunger Halpern, describes her as brilliant but intense, constantly asking insightful questions.
Her influence extends beyond research. Yunger Halpern’s 2022 book, Quantum Steampunk: The Physics of Yesterday’s Tomorrow, brought wider attention to the field. She is also a science blogger, sharing her ideas on Quantum Frontiers. Writing allows her to explore unconventional ideas without the limitations of peer-reviewed research. 'Thinking broadly and creatively is useful for staying inspired in physics,' she says.
Yunger Halpern’s approach to science reflects her personal style: blending the old and the new. Her students, like Shayan Majidy, describe her as both demanding and caring, offering support along with high expectations. Her hobbies lean toward calm activities like walking and visiting museums, but her passion for her work is undeniable. 'She has old-fashioned interests, but she’s a young, energetic rising star in research,' says Majidy."
