The concept that energy is a fundamental driving force behind societal progress has given rise to the notion that a civilization’s technological advancement can be gauged by its ability to harness and utilize energy. In 1964, Russian astrophysicist Nikolai Kardashev devised the renowned Kardashev Scale, which classifies civilizations based on their energy consumption. As of today, our human civilization is estimated to be at around 0.73 on this scale.
The acquisition of energy is crucial for the advancement of civilization. Early societies heavily relied on manual labor and animal power to meet their energy needs. However, the Industrial Revolution in the 18th and 19th centuries brought about a significant shift in how humans utilized energy. With the advent of steam power and subsequent development of coal mining, humanity gained the ability to tap into the vast energy stored in fossil fuels on a massive scale. This facilitated a rapid surge in energy consumption and paved the way for the rise of modern civilization.
While our current way of life places substantial demands on energy, it has also made us remarkably efficient. Today, a typical worker is believed to be ten times more productive than their counterpart from fifty years ago. This unprecedented economic growth witnessed in the past century can largely be attributed to the increased consumption of energy. Therefore, in order to sustain economic growth and strive towards a post-scarcity society, it is imperative that we can secure ever-increasing quantities of energy, preferably from sustainable sources.
Another critical factor is the development of technology to effectively harness these energy sources. This applies to all forms of energy: increasing the temperature at which we burn fossil fuels allows us to extract more energy, while advancements in solar cell design enhance their efficiency. Consequently, the amount of energy we can derive from a source depends not only on its inherent properties but also on our ability to extract and utilize that energy based on our current technological capabilities.
However, recognizing the existence of potential energy sources and having the means to extract them are two distinct aspects. Consider a caveperson stumbling upon a piece of coal—they may quickly realize that it can be used as a tool for cave paintings. Yet, understanding that the same piece of coal can be burned to serve as an energy source is far from obvious.
Furthermore, there is a difference between understanding that energy can be extracted and possessing the technological means to do so. For instance, we are well aware that the sun generates its immense energy output through the fusion of hydrogen atoms into helium. However, replicating this process in a controlled manner within a laboratory setting presents an entirely different set of challenges. Nonetheless, recent technological advancements bring us closer to achieving this ultimate goal.
The emergence of quantum technologies has opened up possibilities for harnessing energy from quantum sources. However, like any technological advancement, quantum technologies are subject to human limitations. Even today, quantum physicists are uncertain about which quantum systems can serve as viable energy sources and which cannot. Moreover, it remains unclear which quantum sources are currently accessible with our existing tools and which may become available in the future.
Researchers at the Institute for Basic Science’s Center for Theoretical Physics of Complex Systems (PCS) have recently developed a measure called observational ergotropy to quantify extractable energy from a source. This measure takes into account the realistic capabilities of our current technology.
Ergotropy refers to the maximum amount of work that can be extracted from a system. Previous measures of quantum ergotropy were based on idealistic assumptions, assuming that experimental capabilities were perfect. This approach is akin to assuming that our fusion plant can achieve the same efficiency as the sun without considering the challenges associated with artificially replicating solar fusion.
In contrast, observational ergotropy provides more practical estimates and updates based on our current technological capabilities. It helps identify the most promising quantum sources for energy extraction given our existing experimental tools.
These findings have implications for determining the optimal platform to realize a quantum battery, an area in which the PCS-IBS team has made significant theoretical advancements. A quantum battery refers to any system that exhibits quantum phenomena and is small enough to be considered as such.
For instance, imagine a line of sixteen atoms trapped using laser technology or superconducting qubits, which companies like IBM and Google are employing in the early stages of building quantum computers. These energy-carrying platforms could potentially power future quantum devices, such as quantum computers, quantum sensors, and devices that enable completely secure quantum-encrypted communication. The researchers at IBS demonstrated how observational ergotropy can differentiate between quantum batteries to identify the most suitable one for powering our quantum-driven future.
Dominik Šafránek from PCS-IBS explains, “As our technological capabilities progress, we can recalculate observational ergotropy. In the future, different sources may be deemed the new ideal, replacing previously optimal sources. This measure has the potential to be continuously used over time and serve as a fundamental tool for evaluating potential quantum energy sources.”
The article has been accepted for publication in Physical Review Letters and is available as a pre-print on the arXiv server.
Source: Institute for Basic Science