Quantum Technologies and Military Strategy

By Ajey Lele

This book is about the strategic relevance of quantum technologies. It debates the military-specific aspects of this technology. Various chapters of this book cohere around two specific themes. The first theme discusses the global pattern of ongoing civilian and military research on quantum computers, quantum cryptography, quantum communications and quantum internet. The second theme explicitly identifies the relevance of these technologies in the military domain and the possible nature of quantum technology-based weapons. This thread further debates on quantum (arms) race at a global level in general, and in the context of the USA and China, in particular. The book argues that the defence utility of these technologies is increasingly becoming obvious and is likely to change the nature of warfare in the future.

• Language: English
• Publisher: Springer
• Release date: Apr 12, 2021
• ISBN: 9783030727215

Book preview

Part ISection I

Anyone who is not shocked by quantum theory has not understood it.

—Niels Bohr

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021

A. LeleQuantum Technologies and Military StrategyAdvanced Sciences and Technologies for Security Applicationshttps://doi.org/10.1007/978-3-030-72721-5_1

1. Quantum Physics: An Esoteric World

Ajey Lele¹  

(1)

The Manohar Parrikar Institute for Defence Studies and Analyses (MP-IDSA), New Delhi, India

Science evolves over different stages: the first stage is that of immature science (pre-science), next stage is about normal science (in which a paradigm is acquired), and the third stage represents revolutionary science and here there is a paradigm shift‏. The period of normal science is based on a given paradigm: a set of theories, methods, metaphysical and epistemological propositions those, at a certain point in history, acquires acceptance. The paradigm postulates the ontology of the world, it dictates on what puzzles the science will possibly work on, and what counts as an adequate solution to such puzzles, it establishes how science should be practiced, and what the aim of science should be. Paradigms, often have anomalies: predictions do not get fulfilled, inconsistencies become visible and few other unconsidered contradictions occur. The structure of scientific revolutions is about normal science with a paradigm and a dedication to solve puzzles. This gets followed by serious anomalies, which lead to a crisis; and finally resolution of the crisis by a new paradigm.¹ Historically, it has been observed that the scientific revolutions bring in major changes in the old paradigm, its theories, approaches and principles. Science has helped us to understand many mysteries in our universe. However, we are yet to get answers for many and possibly this leads to superstation. It is important to look at the science and particularly the progression of science in a ‘scientific’ fashion. Eventually, science is expected to help remove the fear of the unknown.

For long various innovations, discoveries and breakthroughs in sciences has been impacting and enriching the life of humankind. Science has been responsible to make the survival easy for the individuals and society. It also assists humans to improve their living standards. Scientific findings have potential for shaping the vision for the future. The main divisions of science like Physical science, Earth science, and Life science have led to various extraordinary developments, which have impacted the human lifestyle and have made the world a better place to live in. Essentially increased understanding about the basic branches of sciences like Physics, Chemistry and Biology have brought in important advances in range of activities required for the human survival: from water to weather, food to factories and society to security.

Particularly, one of the basic branches of science, the Physics, is known to be playing a very central role towards the overall development of the humankind. This branch of science provides understanding about heat, light, sound, electricity and magnetism. Physics being a fundamental science, is diligently connected to mathematics and also exploits essentials from other branches of sciences mainly biology, chemistry and material sciences. Physics involves studying the natural world. Physics has made it possible to understand the world around us and offers reasons for our existence. Once there was a belief that earth is flat. However, subsequently various philosophers, mathematicians, geographers and physicists gave a precise logic and scientific reasoning for the Earth being round. Normally, Physics gets identified as the study of matter, energy, and their interactions with various other fields. The scope of Physics, ranges from the microscopic level to the macroscopic level. Over a period of time many parts (or types) of Physics have evolved. They focus on different specific fields of study of this science.

Physics is about the rational understanding of nature. The Greek word nature means physics (Greek word Phusika, means natural thing or nature). Possibly, the origin of this science appears to have happened during 15th century. Physics has number of subdivisions, some of them are existing for centuries while some are relatively new. The ‘elementary’ subdivisions of Physics include themes like mechanics, thermodynamics, and electromagnetism. While the modern units of physics include solid-state physics, plasma physics, nuclear physics, quantum physics and cryogenics. There are many more subdivisions, both for early physics (mostly Prehistoric Era) and modern physics. The early physics (say physics up to 1900 AD) actually gets recognised as classical physics. Sir Isaac Newton (1643–1727) and Albert Einstein (1879–1955) who successfully made various theoretical populations are regarded as the fathers of modern physics. They also have made important contributions to the field of classical physics. On various occasions in literature or even otherwise, the terms classical physics, classical mechanics, Newton physics/mechanics are found getting used interchangeably.

Classical physics is about the theories of physics that predate modern, more complete, or more widely applicable theories. Its basis is Newton’s laws of motion. It is also said that the definition of a classical theory depends on context. Classical theory is not about disciplines studying the motion of electrons and the making measurements of atoms and subatomic particles. Most usually classical physics refers to pre-1900 physics, while modern physics refers to post-1900 physics which incorporates elements of quantum mechanics and relativity.² Essentially classical mechanics is governed by laws about the relations between forces acting and motions occurring.

Quantum Physics gets associated with the modern form of physics. This branch of Physics also gets referred as Quantum Science or Quantum Mechanics. The Quantum field is about the study of the microscopic world and its particles. This form of physics, even in the 21st century, is still offering significant challenges to the scientific community. Quantum sciences is considered as one of the most mysterious and exciting fields in physics. In the past, various renowned physicists such as Albert Einstein, Werner Heisenberg, and Erwin Schrödinger are known to have made significant contributions to the quantum thought. This branch of physics gets its mysterious reputation owing to the theories such as particle-wave duality, the uncertainty principle, and the prospect of quantum computing. The research and developments in this arena has made important contributions towards the development of fields like the laser, the internet, personal computers, modern electronics, and many others.³

Human curiosity for physics could said to have begun with a basic query to know more about the universe and about questions in regards to the various activities happening around us. This all is about learning classical physics. The quest to understand the nature could said to have begun with understanding the nature at ordinary (macroscopic) scale. There was an interest to know about our planet, the moon, the stars and other planets. Broadly, this branch of physics could be said to address the issues like predicting the position and velocity of an object at a given time. However, there was an issue in understanding about the nature of extremely small particles moving at very high speed. Classical theories were not able to provide an answer to such problems. These are referred as particles at sub-atomic sizes. Typically, an atom is known to have three subatomic particles, namely: protons, electrons, and neutrons. There are objects in quantum physics which are neither particles nor waves; actually, they present a peculiar combination of both. Quantum theory allows to make probabilistic predictions of the future.

In brief, the main difference between quantum and classical physics is somewhat similar to the difference between a ramp and a staircase. In relative sense, classical physics could be said to be simple and straightforward. In classical physics/mechanics, normally events are known to be continuous in nature, which is to say they move in smooth, orderly and predicable patterns. Projectile motion is a good example of classical mechanics. The ‘continuous’ behaviour could also said to be visible in rainbow. In case of the colours in the rainbow, the frequencies progress continuously from red through violet. In quantum physics, events are unpredictable. In case of electrons, transition between energy levels in an atom could vary from one level to the next. Like, in case of the emission spectra, various colours, indicative of energy level transitions made by electrons, are separated by dark areas. The dark areas represent the area through which electrons make quantum—and therefore dis-continuous—leaps between energy levels. For quantum field, another example could be that of the quantum notion of the ‘complementary nature of light’, which states that light is both a particle, which has mass, and a wave, which has none. This contradictory conception illustrations how peculiar quantum physics can be when compared to classical physics.⁴

There is a significant amount of scientific literature available, which ascertains the difference between classical and quantum physics. However, without getting into any technicalities just for the purpose of broad understating it could be said that, if there are 9 boxes and 10 pigeons, then at least one box will end up with two pigeons. This is in Classical Theory. It is not the same in Quantum Theory. We can pass infinite electrons just from two boxes.⁵ The classical pigeonhole principle was formulated by Dirichlet⁶ in the 19th century and is widely used in number theory and combinatorics. This principle appears obvious and formalizes the fundamental concept of counting. However, it can apparently be violated by pre and post selected quantum systems.⁷

Atoms and sub-atomic particles do not have any commonalities of behaviour with the activities happening in routine life. Their wave properties are not routinely observable. Hence, in order to explain this typical behaviour, characteristics and interactions, scientific community has developed a mathematical model called Standard Particle Model. This model projects two major clusters of elementary particles of matter, i.e. Quarks and Leptons. The model also proposes elementary force carriers identified as Gauge Bosons and one Higgs Boson. Basically, Standard Particle Model links the matter-energy conversions, with the help of Quarks, Leptons, Gauge Bosons and Higgs Boson. Beyond this there could be particles like Gravitation, responsible for Gravitational force, but which does not come under the scope of Standard Particle Model.⁸

Various fundamental forces of the universe follow the laws of quantum mechanics, save one: the gravity. Hence, scientists feel the need to find a way to fit gravity into quantum mechanics. However, this effort remains work in progress and it is expected that any advancement in this field would bring scientists a giant leap closer to a ‘theory of everything’ that could entirely explain the workings of the cosmos from first principles. An initial vital step in that direction to know whether gravity is quantum, is to detect the long-postulated elementary particle of gravity, the graviton. At present, in search of the graviton, physicists are turning to experiments relating microscopic superconductors, free-falling crystals and the afterglow of the big bang.⁹

All in all, Quantum Physics which often gets referred as the learning of the microscopic world has been a challenge for scientific community for all these years. Max Planck¹⁰ (1858–1947) and Albert Einstein (1879–1955), the two physicists of German origin have made significant amount of contributions towards the evolution of quantum and classical theory. It was Plank who simplified the atomic and subatomic processes and Einstein who theorised aspects of space and time (theory of relativity). In addition, there have been important contributions from the physicists like Werner Heisenberg and Erwin Schrödinger.

It is a reality that the subatomic bits of matter don’t follow the same rules as objects those can be seen, felt or held. The quantum world does not work in the way the rest of the world operates. For example, if a ball is hit over a pond then it could sail through the air to land on the other shore. The ball may also get dropped inside the pond and create waves which could ripple away in growing circles. These waves eventually could reach the other side. In both these situations, something travels from one place to another, and only in one case ripples are generated. However, in experiments, particles in the subatomic world occasionally travel like waves. And on some other occasions they travel like particles. Consider photons, the particles that make up light and radiation. It is a reality that the light could sometimes act like waves, and sometimes act like particles (called photons). During some specific experiments’ phonons are known to behave like the particles and in some other cases they behave like waves. It is not possible to measure them as waves and particles at the same time. Fundamentally, because of all this, Quantum Theory is a challenge. Over the years, it both enthused the thrills for scientists as well as frustrated them. For the scientific community, the excitement is still there since the theory has the experimental backing. Various experiments are known to have verified the accuracy of quantum predictions. However, this journey has never been easy and more importantly is not over yet.

Albert Einstein (1879–1955) is known to have worked extensively on quantum theory during the early 20th century and has expressed frustrations about working on this subject. Werner Heisenberg (1901–1976) opined that ‘The concept of the objective reality of the elementary particles has thus evaporated’. He further argues that ‘The idea of an objective real world whose smallest parts exist objectively in the same sense as stones or trees exist, independently of whether or not we: observe them… is impossible’. On the other hand, Richard Feynman (1918–1988) was more dramatic. He said that ‘I think I can safely say that nobody understands quantum mechanics’. While Niels Bohr (1885–1962) was straightforward. As per him, ‘The indivisibility of quantum phenomena finds its consequent expression in the circumstance that every definable subdivision would require a change of the experimental arrangement with the appearance of new individual phenomenon’.¹¹

Scientists have tried to understand this theory initially, by conducting some simple experiments. To help describe it, they have used ‘thought experiments’. Such experiments are basically devices of the imagination and are employed for various purposes such as education, conceptual analysis, exploration, hypothesizing, theory selection and implementation.¹² In this context, the most cited experiment has been the Schrödinger Cat (Erwin Schrödinger, 1887–1961). As a start point, he imagined a sealed box with a cat inside. He imagined that the box also contained a device that could release a poison gas. So, if such gas gets released, then it would kill the cat. It was assumed that the probability for the release of the gas is 50%. So now the only way to know if the poison was released and whether the cat was dead or alive, was to open the box and look inside. There could be only two possibilities that either the cat could be alive or dead.¹³ However, the catch is that, if the cat behaves like quantum particles, then the outcome of the story would be abnormal. A photon, for instance, can be a particle and a wave. Likewise, Schrödinger’s cat can be alive and dead at the same time! Therefore, the broad argument was that, until the box gets opened, the cat could be believed to be, both ‘dead and alive’ at the same time.

Actually, this Schrödinger’s ‘mind experiment’ to prepare a cat in a ‘superposition’ of both alive and dead states could be viewed as a crux of quantum mechanics. Superposition gets recognised as one of the fundamental principles of quantum mechanics (physics). In classical physics, a wave relating to a musical tone can be seen as several waves with different frequencies that are added together and superposed. Correspondingly, a quantum state in superposition can be seen as a linear combination of other distinct quantum states. A typical example visualizing superposition could be understood by famous experiment in physics called the double-slit experiment. This Thomas Young’s double-slit experiment uses a very feeble light source that spits out one photon at a time, leading to the same evidence of interference, although there are no waves as such to interfere with each other. The only way the single photons can experience interference, when each photon somehow goes through both slits simultaneously (this happens due to superposition) and interferes with itself. It is important to note that, in reality, superposition can never actually be observed. What we know is the consequences of their existence, after individual waves of a superposition interfere with each other. This means, we can never observe an atom in its indeterminate state, or being in two places at once. In practice, we never observe a quantum system directly; we only observe its effect on its environment.

One of the other counter-intuitive phenomena in quantum mechanics (physics) is ‘entanglement’. A pair or group of particles is entangled when the quantum state of each particle cannot be described independently of the quantum state of the other particle(s). The quantum state of the system as a whole can be described; it is in a definite state, although the parts of the system are not. Quantum entanglement could be identified as an exchange of quantum information between two particles at a distance, while quantum superposition describes the uncertainty of a particle (or particles) being in several states at once (this could also involve the exchange of quantum information for a particle that is known to be in several locations simultaneously).¹⁴

For physicists there are two separate rulebooks for explaining how nature works. The general relativity, accounts for gravity and its domination on the orbiting planets, colliding galaxies and overall dynamics of the expanding universe as a whole. Then there is quantum mechanics, which address the other three forces—electromagnetism and the two¹⁵ nuclear forces. Quantum theory is extremely adept at describing what happens when a uranium atom decays, or when individual particles of light hit a solar cell.¹⁶ The Quantum Field Theory (QFT) arose out of our necessity to describe the transient nature of life. This theory is needed since there is a simultaneous confrontation amongst special relativity and quantum mechanics. Classical physics (mechanics) is incapable to explain phenomena like superfluidity, superconductivity, ferromagnetism, Bose-Einstein condensation etc. Likewise, quantum physics (mechanics) is incompatible with general relativity. The additional problem areas of this theory are some interpretation ambiguities of mathematical structure.¹⁷

Assume a fast-moving rocket ship close to light speed. Here there is a need for factoring the special relativity while for a low moving electron scattering on a proton, there is a need to summon quantum mechanics. When there is a peculiar confluence of special relativity and quantum mechanics then a new set of phenomena arises: particles can be born and particles can die. It is this matter of birth, life, and death that requires the development of a new subject in physics, that of QFT. In quantum physics, the uncertainty principle explains that the energy can fluctuate wildly over a small interval of time. As per the special relativity, energy can be converted into mass and vice versa. With quantum physics and special relativity, the wildly changing energy can metamorphose into mass, that is, into new particles not previously present.¹⁸

There are different ideas about the forces that govern the world. Various theories of classical mechanics have their own relevance and they continue to matter in the quantum era. Various aspects of quantum mechanics still remain unresolved. During 1960s, physicist John Bell had proposed a way to test quantum mechanics recognized as Bell’s inequality. Here the idea is that two parties, nicknamed Alice and Bob (or A and B), make measurements on particles that are located far apart, but connected to each other via quantum entanglement.¹⁹ Presumably, if the world is governed solely by quantum mechanics, these remote particles would be governed by a nonlocal correlation through quantum interactions, like measuring the state of one particle impacts the state of the other. But, some alternate theories indicate that the particles only appear to affect each other, but in reality they are linked by other hidden variables following classical, rather than quantum, physics.²⁰ Researchers have conducted many experiments to test Bell’s inequality, but with limited success. Presently, research is continuing on this subject.

Although quantum physics looks at how particles in nature ‘come together’ and bring along their unique properties, such as electrical conductivity or magnetism however, it has been very difficult for the researchers to get more than a glimpse of these complex phenomena. This is because of the enormous number of particles these phenomena contain (over one billion-billions in each gram) and an enormous number of interactions happening between them. Now scientists are looking at options like Artificial Intelligence (AI) to find answers to such challenges. It has been demonstrated that the algorithms based on deep neural networks could be of some use to better understand the world of quantum physics, too. Such algorithms, which are already been in use in the field of facial and voice recognition capabilities, can now be harnessed to understand the quantum behaviour of the nature.²¹

There is a view that the process of photosynthesis, which green plants and some bacteria turn sunlight into chemical energy, actually gains light-harvesting efficiency by exploiting the phenomenon of ‘quantum coherence’. This comprises the superposition of electronic quantum states that seem able to explore many energy-transmitting pathways at once. If this view is correct then it could be said the quantum mechanics is assisting the fundamental energetic processes those drives all life on the surface of the Earth. However, there are different opinions in scientific community on this. Though the observations show that there is correlation between the wave functions of the states involved in energy or electron transfer, but these effects are not recognised by some from the scientific community as truly a quantum coherence activity, in the sense that entangled states of quantum computing are understood. For this, there is a need to correctly understand how plants or other photosynthetic organisms are able to transfer energy and electrons on an ultrafast timescale in the right direction with high quantum efficiency. Such knowledge holds crucial lessons about how to engineer human-made systems with the capacity to convert sunlight energy to electrochemical energy to produce electricity.²²

Interestingly, the word quantum normally gets viewed with different interpretations under different settings. In literature, generally this word gets mentioned as the minimum amount of any physical entity. Prevalent contemporary understanding this word denotes to the smallest thinkable discrete unit of any physical property, such as energy or matter. Quantum is the Latin word for amount. Actually, three different Latin words could be mentioned in this context. They are quants, quanta and quantum. Broadly, they indicate the meanings like how great, how much/many and of what size/amount/degree/number/worth/price. From the point of view of physics, the usage of word quantum happened around 1900, when the physicist Max Planck used it in a presentation to the German Physical Society. Physics and its various braches do have some Latin roots.

Various discoveries in quantum physics are changing the existing definitions of nature, matter, space, life, and agency. Various new ideas in this field are found allowing science to overcome the myth of dualism, the illusion of objectivism, and the metaphor of reflection, challenging the notions of determinism, certainty, and fixity in favour of conceptions of dynamism, uncertainty, probability, symmetry, multiplicity, and complexity. With such a conceptual framework, quantum mechanics articulates the existence of permeable worlds with sedimenting effects in the unfolding of the phenomena.²³

Broadly, since 19th century onwards much development in the field of sciences in general and physics in particular have taken place. Physics could be said to be responsible for raising some fundamental questions and trying to find answers to them. On various occasions such answers are found been given initially in the