The Power and Potential of Quantum Information
Quantum entanglement is a complex phenomenon in physics that is often described as a link between two distant quantum objects that allows one to affect the other instantly. However, this description as “spooky action at a distance” is inaccurate and misleading. In reality, entanglement is better understood as information.
In 1935, physicist Erwin Schrödinger coined the term “entanglement” and emphasized that it was a fundamental characteristic of quantum mechanics that distinguishes it from classical physics. Schrödinger was responding to a famous paper by Einstein, Podolsky, and Rosen (EPR) that argued quantum physics was incomplete.
The EPR argument challenged the conventional understanding of reality as a collection of things with physical properties waiting to be revealed through measurement. Einstein’s theory of relativity supports this view, but it also requires that reality be local, meaning that nothing can influence anything else faster than the speed of light. EPR showed that quantum physics is incompatible with this view of reality.
To complete quantum physics, Einstein proposed the existence of a deeper theory of local reality, but this was challenged by Bell’s experiment in 1964, which could rule out the existence of local reality. Clauser, Aspect, and Zeilinger subsequently improved and performed the experiment.
Quantum physics often describes entanglement as a phenomenon where two particles are linked regardless of their distance from one another. This is a popular but inaccurate explanation. In fact, quantum physics is not concerned with the actual state of the world, but rather the probabilities of the outcomes of experiments we conduct to test our theories. This misinterpretation is partly due to the way physics is traditionally taught.
The author teaches quantum physics to computer science students and guides them to understand quantum entanglement by engineering quantum phenomena without invoking the spookiness of the phenomenon. Students who were taught in this way were able to understand the 2022 Nobel Prize in Physics better and had less trouble grasping the concept of spookiness.
The common method of teaching entanglement starts with Einstein’s local realism and often ends up invoking free will of the experimenter. Instead, understanding the concept of entanglement as information, not physics, is a more accessible and straightforward approach. For instance, the author provides an analogy of two people implicated in a crime and how their answers to two questions are linked despite being in separate rooms.
The analogy illustrates how two particles can be entangled, and how their responses are linked regardless of their distance, without invoking spookiness or free will of the experimenter. This helps to demonstrate how quantum entanglement departs from classical physics.
Alice and Bob had only used classical information until they started sharing quantum information, which allowed them to succeed with a probability higher than 75%. To achieve this, they used the principles of quantum information rather than classical information and created a strategy.
Understanding the solution they created requires some knowledge of linear algebra, so the author doesn’t go into detail. However, it is important to note that the quantum information they shared requires correlations, which makes it entangled.
Investigators were initially alarmed by this entanglement because they were only familiar with classical information. However, correlations are present in all theories of information, making entanglement a common occurrence.
Looking at entanglement through the lens of quantum information, it is not considered strange or rare, but rather expected. This perspective highlights the issue with demanding a classical description of quantum phenomena.
The Nobel Prize winners were the first to prove this as a fact of nature. Now, individuals can create their own entanglement and process the correlated quantum information on a real quantum computer, following in the footsteps of the Nobel Prize winners.
Einstein had hoped to explain all of nature using a concise and straightforward classical description, but we now understand that the most precise depiction of nature is provided by quantum information, which is expressed in a language we are unfamiliar with. Embracing this concept frees us from the boundaries of conventional physics and enables us to teach it in a more intuitive way that promotes active learning. The perspective of quantum information sheds light on some of the most significant queries in physics. For instance, quantum information holds the key to unraveling the enigma of black holes and perhaps even the entire cosmos. Moreover, it leads to the creation of innovative quantum technologies that can swiftly and automatically encode and handle quantum information.
The use of classical information has been prevalent until Alice and Bob discovered that sharing quantum information can increase their success rate by over 75%. They achieved this by creating a strategy that relied on quantum information instead of classical information. The process involved the use of linear algebra, which requires a level of familiarity to understand. The quantum information they shared required correlations, which meant it was entangled. Although this seemed spooky to investigators who only reason with classical information, it is a common occurrence in any theory of information. Entanglement is not strange or rare but rather expected when viewed through the lens of quantum information. This perspective sheds light on the core problem with demanding a classical description of quantum phenomena as it is the wrong language. The Nobel Prize winners were the first to demonstrate this as a fact about nature, and today anyone can create entanglement and process the correlated quantum information on a real quantum computer.
The limitations of traditional physics have been lifted with the acceptance that quantum information provides the most accurate description of nature. Although the language used to describe it is unfamiliar, it facilitates active learning and provides insight into some of the most profound questions in physics. The quantum information perspective has led to the understanding of the mysteries surrounding black holes and the universe as a whole. It has also led to the development of new quantum technologies that encode and process quantum information.
In the latter half of the 20th century, computers transformed every aspect of society, leading us to believe that they were the ultimate tool for this purpose. However, scientists now believe that quantum computers will be the ultimate machine, with unlimited potential that is yet to be fully realized. Although it is difficult to predict when they will become ubiquitous or what problems they will solve, quantum computers have already been shown to be capable of solving a small list of problems, such as factoring numbers, searching databases, and simulating chemical reactions. Those who have such problems may find quantum computers to be an effective solution, but Einstein would have been unlikely to share this sentiment.