Interview with Prof. K. Fujii

The followings are the summary of the discussion by LilysAI.

0.1 📌 Current Status and Future Prospects of Quantum Computers?

Currently, quantum computers are at a scale of tens to hundreds of qubits. Real-world implementation requires a scale of 1 million qubits. At this pace, it is thought that this could be realized around 2040-2050.

0.2 💡 Key Application Areas of Quantum Computers?

Simulation of matter and molecules (drug discovery, materials development, etc.)
Quantum AI (acceleration and improved accuracy of machine learning)
Probability calculation and simulation in the financial field
Cryptanalysis (theoretically possible, but practical implementation is still a ways off)
Quantum error correction (noise countermeasures)
Quantum sensing (high-sensitivity measurement technology)
Quantum networks (secure communication)

This video features Professor Keisuke Fujii of Osaka University, who provides a comprehensive 90-minute explanation of quantum computers. Quantum computers apply the principles of quantum mechanics and have the potential to perform calculations much faster than conventional computers, which have difficulty with certain computations. The video discusses the possibility of quantum computers revolutionizing the world by 2050, Japan’s strategy to catch up with the US and China, and how to utilize quantum computers in business. It also explores the hype and winter cycles associated with quantum computers, clarifies misconceptions about quantum supremacy, and delves into the essence of quantum computers, with a focus on the quantum native era. Viewers will be able to deepen their understanding of the future opened up by quantum computers by learning from a leading-edge researcher.

Quantum Computers: Quantum computers are next-generation computers that use the principles of quantum mechanics to perform calculations. Because they process information in a completely different way from conventional computers, they have the potential to solve certain problems dramatically faster…

0.3 📘 Current Status and Challenges of Quantum Computers

Quantum mechanical superposition has the fundamental characteristic that no one knows whether the result is 0 or 1.
Players around the world are conducting research on quantum computers, and the situation is constantly changing.
The hype and winter cycle regarding quantum computers may arise from a discrepancy between the actual image and expectations.
The difference in computational complexity between quantum computers and classical computers is clear; quantum computers allow for natural computation, while supercomputers require forced simulation, which takes time.
The current evolution of quantum computers is rapid, and in particular, advancements in technology are being promoted through comparison with supercomputers.

0.3.1

On the Evolution of Quantum Mechanics and Quantum Computers

Quantum superposition is something that no one can understand whether its state is 0 or 1.
The current competition is very intense, with the number of players increasing worldwide, and the updates in technology happen instantly, so it’s described as being in a state of constantly sprinting.
Quantum research is emphasized as progressing in a way that anticipates the future, like a time machine.
The interest in quantum AI and quantum computers is demonstrated by researchers with deep passion, and this evokes a kind of enthusiasm like the pursuit of idols.

0.3.2

Development and Future Predictions of Quantum Computers

Quantum computers are considered by experts to be a turning point in human civilization. This is a technology that has the potential to greatly change the future of humanity.
Japan is said to have the potential to catch up with China and the United States in the race surrounding quantum computers. The operation of domestically produced quantum computers has begun, and expectations are rising.
Information about quantum computers can often be misleading, and researchers are focusing on controlling the gap between the actual technology and expectations. This is because the phenomenon called hype is considered a problem.
The history of quantum computers goes back to the 1980s, and the appearance of cloud-available technology after 2010 is attracting attention. Modern quantum computers are at a turning point, as exemplified by the evolution of AI.
It is estimated that it will take another 20 years, like the evolution of AI, for quantum computers to create value in society. How technological innovation progresses in the future is key.

0.3.3

Commercialization of Quantum Computers and Its Challenges

Although the announcement of Google’s quantum supremacy became a topic, there are discussions about its feasibility, and it is not considered perfect.
Company D played a pioneering role in quantum devices, but its quantum computer does not have universal computational capabilities and is limited to specific applications.
In special applications compared to conventional computers, dedicated hardware may be more cost-effective.
The problem Google’s quantum computer solved took 10,000 years to solve on a supercomputer, temporarily demonstrating the superiority of quantum computers.
Developers of supercomputers are seriously seeking countermeasures in response to the evolution of quantum computers, and the evolution of quantum computer simulation technology is seen.

0.3.4

Differences between Quantum Computers and Classical Computers

Quantum computers are based on physical laws, so it is possible to simulate physical equations on supercomputers, but there is a difference between implementation as a device and simulation on classical computers.
Even if the results are the same, the computational complexity required to obtain them differs greatly between quantum computers and classical computers, and quantum computers can perform calculations more easily.
Classical computers have to perform simulations forcibly, and the time required for that increases exponentially.
Quantum computers are expected to exhibit efficient performance relative to the volume of calculations.

0.3.5

Importance of Understanding Quantum Computers and Classical Computers

Mr. Take is preparing to review the differences between quantum computers and classical computers.
It is also shown that he has read many books to deepen his knowledge of quantum computers.
He emphasizes the importance of firmly grasping the basic knowledge for further discussion.

0.4 🧪 Progress and Challenges of Japan’s Quantum Computer Technology

The quantum computer at the RIKEN is a superconducting type, and the cooling temperature is 10 mK, which is almost absolute zero, and it maintains the operating accuracy of the quantum computer by reducing noise.
Although superconducting materials that function at high temperatures have appeared, extremely low temperatures are still required from the viewpoint of the energy of quantum bits and noise countermeasures.
Japan is one of the few countries that can provide a quantum computer that operates with 50 or more qubits, and expectations for future research and development are rising.
The national budget investment is 2.5 billion yen, which is a relatively low budget, and is considered to be cost-effective at this stage compared to the large-scale investments of the United States and China.
In the future, larger project scales and human resource development will be required, and it is said that it would be good if it grows to a 100 billion yen scale, but it is thought that securing funds and human resources will be important for that.

0.4.1

The Quantum Computer at RIKEN and Its Cooling Technology

Japan is said to have caught up in quantum computer development with the superconducting quantum computer announced by RIKEN.
This quantum computer uses a refrigerator, and the coldest part reaches 10 millikelvin.
The reason for cooling to near absolute zero is that objects with temperature emit electromagnetic waves, which become noise and destroy quantum properties.
Extreme cooling is required because noise from electromagnetic waves has a negative impact on the operation of quantum computers.

0.4.2

Quantum Computers and the Noise Problem

In order to protect quantum computers from noise, it is necessary to cool them to a very low temperature, and a temperature of about 10 mK is required.
Even if high-temperature superconductors are developed, cooling is necessary because the energy of the qubits manages noise with electromagnetic waves of 5 GHz to 10 GHz.
Noise countermeasures are a critical issue in the performance of quantum computers, and quantum phenomena do not affect classical operations if there is no noise.
RIKEN’s achievements are considered to have brought significant progress to the noise problem.
The institute is located in Wako, Saitama Prefecture, and there are many researchers in its vicinity.

0.4.3

Progress of Japan’s Quantum Computers and Its Impact on Business

Japan is said to have caught up with the United States and China in terms of quantum computer development, and it is currently the fourth country to have a computer that operates with 50 or more qubits.
Google’s hardware development began in 2014 and reached supremacy in 2019, while Japan also started a similar project in 2018 and has made progress in the same five years.
Approximately 2.5 billion yen in national funds has been invested in the development of quantum computers, and the project is progressing with a low budget compared to other big science projects.
While major companies (e.g., Microsoft) are investing tens of billions of yen in AI, quantum computer research in Japan is relatively inexpensive, so research is expected to be promoted.

0.4.4

The Roles of Quantum Computers and Supercomputers

In the future, it is considered that human resources and funds are necessary in order to compete with other countries.
It is estimated that the development of supercomputers will require a project on the scale of 100 billion yen.
Supercomputers are not in a competitive relationship with quantum computers, but rather, they should be used to contribute to the creation of the next quantum computer.
It is recognized that it is important to expand the frontiers of science and technology by utilizing the computing power of supercomputers.
In particular, the possibility of unexpected applications is expected, and versatility is expected in the method of utilizing computing power.

0.4.5

The Potential of Quantum Computers and Cryptanalysis

New applications beyond the scope of current technology are expected for the use of quantum computers.
If a huge quantum computer is realized, it is said that prime factorization can be performed efficiently, which may affect current encryption technology.
RSA encryption, etc., is based on the difficulty of prime factorization, so cryptanalysis by quantum computers may become a reality.
If quantum computers advance, it is thought that better application methods will be discovered in addition to cryptanalysis.

0.4.6

The Relationship between Quantum Computers and Physical Simulation

Quantum computers excel at the simulation of quantum systems.
Richard Feynman stated that in order to simulate quantum systems, a computer built on the principles of quantum physics is needed.
Information has a physical form and follows physical laws, and there is a problem that it cannot be accurately simulated in classical physics.
Due to the problem of scaling of computation time, the conclusion is that the research and development of quantum computers is essential.
Due to the complexity of the calculations, there is a risk of hitting a wall in the future, so research on quantum computers is important.

0.4.7

Differences between Classical Computers and Quantum Computers

Classical computers represent information with classical bits, which have clear states of 0 and 1, while quantum computers utilize qubits that have a state of superposition, allowing them to handle both states simultaneously.
Due to the principles of quantum mechanics, things are permitted in a state that is not black and white, that is, a superimposed state, making it possible to process information beyond classical understanding.
When a coin is flipped, the state of spinning around is not clearly either heads or tails, but its state cannot be determined until it is observed, which is similar to the characteristics of a qubit.
In reality, the state is determined by observation, so in the quantum world, uncertainty is rooted as something known by God.

0.5 🚀 New Perspectives on Quantum Computers

Quantum mechanics is based on the concept of superposition, and it is said that no one can know the state accurately, but it can be said that this is directly connected to the possibilities of quantum computers.
In the algorithms of quantum computers, the class of the problem does not change regardless of which interpretation is adopted, so it can be considered that either interpretation is fine from a practical perspective.
As examples of the use of quantum computers, molecular simulation and probabilistic simulation are cited, and it is expected that calculations that cannot be handled by conventional computers will become possible.
Quantum computers have the potential to create new value through even meaningless calculations being incorporated into social systems, and such applications are considered to be “killer applications.”
The number of qubits required for error correction is vast, and it is predicted that it will take about 20-30 years to reach the goal, but if it is reached, a theoretically guaranteed quantum computer will be realized.

0.5.1

The Concept of Superposition in Quantum Mechanics

Quantum mechanical superposition has the characteristic that, in theory, no one can completely know its state.
In physics, the concept of superposition is considered essential to explain certain physical phenomena.
Professor Fujii supports the usual Copenhagen interpretation, but he stated that he does not have any particular bias towards it.
The interpretation proposed by David Deutsch is also mentioned, but further explanations are not provided.

0.5.2

Relationship between Quantum Computers and Interpretations

The class of problems that quantum computers can solve is said to remain the same regardless of which interpretation is used.
The importance of interest in solving problems based on the rules of quantum mechanics, and interpretation can function as an inspiration for it.
David Deutsch is asserted to be advancing algorithm discovery using the many-worlds interpretation.
The concept called cubism is considered unstudied and does not attract much interest.

0.5.3

Comparison between Quantum Computers and Traditional Physics

Traditional physics is about observing the laws of nature and understanding the rules.
On the other hand, in the field of quantum computers, it is emphasized that the observer themselves intervene in the micro world and control it while interacting with nature.
Taking “Go” as an example, even if you know the rules, researching quantum computer algorithms is similar to finding game strategies and strong moves.
It is important to understand the rules of quantum mechanics and then explore how to enjoy and play advanced games based on those rules.

0.5.4

The Appeal of Quantum Computers and Understanding Superposition

Quantum computers are attractive to people interested in both physics and computers.
Because there is no analogy in everyday life, understanding the state of superposition is difficult, but it becomes easier with the use of examples.
The example of the grateful crane shows the superposition state where the states overlap and there is a possibility of becoming one or the other when the sliding door is closed.
By peeking, the state is determined to be 0 or 1, so it is emphasized that the act of observation affects the nature of superposition.

0.5.5

The Principle of Quantum Computers and the Possibility of Practical Implementation

Quantum computers are said to make it possible to simulate the world that could not be captured before by utilizing the principles of quantum mechanics.
Based on the quantum mechanical behavior of the electrons of water molecules (H₂O), the calculation is expected to be accelerated naturally in molecular simulations using quantum computers.
One of the well-known algorithms is prime factorization, and demonstrations of quantum computers are also being conducted in this field.
The use of quantum computers will make it possible to perform various other calculations, and research is progressing.

0.5.6

Application Possibilities of Quantum Computers

Quantum computers are exploring applications in the fields of finance and AI, and the term quantum AI even exists.
The calculation, such as random quantum circuit sampling shown in Google’s quantum supremacy, can be done quickly compared to conventional supercomputers, but it is sometimes considered useless at first glance.
A system like blockchain, which is a system where meaningless calculations contribute to the safety of payments, is one example of utilizing the characteristics of quantum computers.
It is possible that the context of a natural calculation task by a quantum computer will come to have meaning, and that may become the key to the future killer application.

0.5.7

New Era Prospects for AI and Quantum Computers

AI can make moves that exceed human understanding in games such as Shogi and chess, and there is a similarity between AI and quantum computers because this also applies to quantum computers.
Quantum computers have the potential to create new systems in security, etc., and it is considered that it will be a technology with such influence.
Quantum technology is expected to be used in a wide range of applications, including not only calculations but also cryptographic security and sensing, and even medicine.
A large number of qubits are needed for error correction, and it is said that it will take 20 to 30 years for a quantum computer to become theoretically guaranteed.
The quantum computer native generation will accept quantum theory like a programming language and may create new innovations.

0.6 🌀 Practical Implementation of Quantum Computers and Entanglement

In the early stages of quantum computers, they were regarded as analog computers, and it was thought that digital precision could not be guaranteed, but it is possible to protect against errors by utilizing quantum entanglement.
Entanglement is a quantum correlation between particles far apart, and, for example, it shows that particles in Osaka and Tokyo can have a specific state at the same time.
By utilizing the unique properties of entanglement, secure random numbers can be shared between two parties far apart, ensuring security against tunnels and eavesdroppers.
Current quantum computer technology is still in its infancy, similar to the development of modern computers, and it is estimated that it is a stage where potential has not yet been fully realized.
As projects and research progress, Japan has established a stable research environment led by the government, differentiating itself from other countries in the development of quantum computers.

0.7 🧠 Progress and Future Prospects of Quantum Computers

Current quantum computers can perform basic tasks such as distinguishing between 0 and 1, but it is speculated that large-scale quantum computers will play an important role in machine learning tasks in the future.
Setting specific milestones as the number of qubits increases is considered important for sustainable technology development.
The number of qubits is expected to increase from 2030 to 2040, reaching 1,000 qubits in 2030 and 1 million qubits in 2040, but there are many technical challenges in this development.
China is investing heavily as a national project and developing quantum computers, but a lack of human resources is a major obstacle in international competition.
Although Japan has a relatively well-established education system for quantum computers, there are still few female researchers, so it is considered that securing more diverse human resources is required.

0.8 🚀 Quantum Computer Business and the Potential of Future Technology

It is said that quantum computer-related startups are not purely making sales, but are raising funds through investments from venture capital and joint research with companies.
Quantum computer technology has the potential to spin off related technologies, such as precise control and sensing technology, and is also expected to be applied to medicine and environmental technology.
It is important for Japan to have technology, and in particular, it is necessary to consider the future military use and the influence on cryptographic technology that quantum computers have.
The currently evolving quantum technology is expected to bring about a qualitative change in data and information processing in the future, and the need for quantum machine learning and quantum AI is predicted to increase.
Ultimately, it is desired to contribute to solving climate change through artificial photosynthesis and as new energy solutions by quantum technology.

0.8.1

Quantum Computer Business and Fundraising

It is said that quantum computer-related startups mainly raise funds through investments from venture capital and joint research with companies.
In order for companies to purely develop algorithms, specialized personnel are needed, and there are difficult challenges in research and development.
Research on quantum computers offers opportunities to become an early adopter, and companies and research institutions may be able to get ahead of new technologies.
It is also suggested that research on quantum computers will, like past examples (the Apollo project and elementary particle experiments), spin off new related technologies.

0.8.2

Initialization Techniques for Quantum Computers and Their Impact on Business

The technologies developed to build quantum computers include precise control technology and sensing technology.
The technology that uses NMR (nuclear magnetic resonance) is the technology to align nuclear spins for the initialization of quantum computers, which improves sensitivity.
Molecules in the body are in a high-temperature noise environment, and by striking a parking in the initialized nuclear spin, metabolism can be confirmed with high sensitivity by NMR.
The ripple effect from quantum computers on business may be 10 to 30 years away, but the technology has already entered the experimental stage.

0.8.3

Quantum Computers and National Strategy

Research funding should be allocated with an emphasis, and its importance as a national policy is emphasized.
It is pointed out that defense and the military are likely to be interested in quantum technology, and historically, the development of the Internet was due to strategic involvement by the nation.
Current quantum computers are not necessarily useless militarily, but it is considered that possessing the technology itself is important.
Quantum technology may be utilized for sensing and fishermen’s communication, and quantum internet is also attracting attention, so Japan is required to maintain cutting-edge technology.
The future of quantum technology is uncertain, but it is important to have it widely, and it is said that Japan as a whole needs to make an effort to maintain the technology.

0.8.4

The Future of Quantum Computers and Cryptography

It is considered that technology to counter hacking will be needed in the future. This is to counter quantum computers that may break a country’s cryptography.
Understanding the security of cryptographic technology is important, and specifically, it is necessary to know the risks when current quantum computers get serious.
The impact of quantum computers in 10 years may be even more serious, and the need for new encryption to maintain secure communication is emphasized.
Finding problems that quantum computers are not good at can be a clue to finding secure communication methods.
It is important to coolly assess current and future technologies in the evolution of cryptographic technology.

0.8.5

Current Status and Necessity of Quantum Computer Research in Japan

Because there are very few researchers in quantum computer research in Japan, it is considered necessary to put all efforts into it.
Osaka University and Keio University have IBM hubs, and they are developing quantum computers, but the number of research labs has not increased.
Only one research lab has been established in each university, and it is pointed out that the startups in the University of Tokyo are still few as an issue.
It is recommended for junior high and high school students who aspire to research to read related books.

0.8.6

Current Status of Research and Publication of Papers

Currently, AI research is rapidly spreading through sharing on preprint servers, and it is thought that the number of papers is increasing rapidly.
In the field of mathematics, the culture of early publication of papers has been established, and objective evaluation standards are emphasized compared to other fields.
Some AI researchers have many unpublished studies, and it is pointed out that it is difficult to censor the quality of individual studies.
The site “Cylate” provides a ranking of papers uploaded to the archive and visualizes the degree of acceptance of papers.
Papers written by famous researchers tend to be popular and their evaluation tends to increase, but it is said that at least a minimum quality is ensured.

0.8.7

Rapid Progress in Quantum Computer Research

It is felt that research on quantum computers has progressed rapidly compared to around 2006, and the research environment is in a difficult situation.
The research environment used to be peaceful, but now many players are participating, and competition is intensifying, so research results are published immediately.
If you conduct research on the same theme, the timing of announcing the results is a matter of life and death, and a delay of one week creates a fatal difference.
The competition is like a non-stop 100m sprint, and it feels like you need to keep running at full speed.
It is presumed that this harsh environment is a source of anxiety for new researchers.

0.8.8

Challenges and Possibilities in the Quantum Computer Field

Quantum computers are a new field, and there are many possibilities, so they hope for the participation of younger generations.
In the research conducted in 2018, a proposal for a quantum computer applying machine learning algorithms was a big hit, and it is stated that there are currently 800 to 900 examples of use.
Research is important for out-of-the-box ideas and new challenges, and it is argued that not only talent but also curiosity and the desire to do new things are necessary.
In quantum computer research, problem setting is important, and it is emphasized that it is necessary to break away from conventional methods and carve out a new path.

0.8.9

Long-Term Perspective for Utilizing Quantum Computers in Business

Because quantum computers are not a technology that generates profits in the short term, long-term perspectives are required for their development in the business world.
Information in the media is exaggerated and easily misunderstood as being immediately usable in business, but in reality, a long-term plan is necessary.
In particular, future contributions are expected in the pharmaceutical and automotive industries, but it is emphasized that several years of preparation are essential for practical implementation.
Because it is too late after the computer is completed, it is important to develop the method of use early on.
For that, it is suggested that a long-term approach and the training of in-house personnel are necessary.

0.8.10

Quantum Computers and the Future of Humanity

Professor Fujii stated that he wants to know the future of human science and technology through quantum computers, and he showed expectations and skepticism about the arrival of singularity. He says that recent technological advances may be bringing the singularity closer, but he is also concerned about the destabilization of human society that comes with it.
Quantum computers suggest the possibility of contributing to cancer treatment, environmental issues, and especially solving climate change. It is pointed out that, technically, it is possible to overcome cancer, and specifically, the real-time determination of the effect of anticancer drugs and early treatment of cancer with quantum beams are given as possibilities.
It is thought that quantum machine learning and secure cloud computing will be realized with the progress of quantum computers. In a society overflowing with quantum data, quantum AI needs to understand and predict that data, and that future image is expected.
As the moonshot for quantum computers, the aim is to realize quantum error correction, and if this succeeds, computational power will be dramatically improved. This changes the quality of the calculation of quantum computers, and further breakthroughs are expected.
As the concept of quantum evolves, Professor Fujii stated that the “quantum native” era will arrive, and mentioned the possibility that the values and structures of society will change. It is indicated that the idea that the characteristics of the modern society which requires diversity match with the characteristics of quantum.