12: Chapter 12 A New Branch in the Technology Tree: Topological Quantum

Outside the capital, at a newly commissioned, high-security auxiliary research base for the Chasing Light project.

It was far from the city, hidden behind a dense ecological shelter forest; the surface buildings were low-key and simple, but the underground was a world of its own.

Lin Shen's new studio was on the second underground level.

The room was spacious, bright, and maintained a constant temperature and humidity, equipped with the most advanced photonic device design and testing platform available in the country.

On one wall was a massive splicing screen; one half displayed complex silicon-based photonic integrated circuit layouts and simulation results, while the other half continuously scrolled through the latest summaries of quantum computing materials from the firefly knowledge base.

It had been two weeks since his return from Star Continent.

In these two weeks, the world had been in an uproar over the sudden emergence of athena.

International media reported extensively, hailing athena as a "milestone in human computing history" and the "engine of the new industrial revolution."

The federal government struck while the iron was hot, announcing the establishment of the "Global Quantum Alliance" initiative, using the bait of opening up partial cloud computing access and technical standards for athena to try to win over and divide the scientific research forces of other countries and regions, building a quantum ecosystem with the federation at its core.

Public opinion in the Long Kingdom, after a brief period of shock, anxiety, and debate, quickly shifted under state guidance to a more rational and positive tone of "facing the gap squarely and firmly catching up."

The official stance continued to emphasize "independent innovation" and "open cooperation," but internally, especially in relevant technological fields, the tension was palpable.

The atmosphere at the Chasing Light project headquarters meeting was heavy.

Academician Qin pointed out that the appearance of athena marked the entry of competition for basic computing capabilities into a completely new stage.

Due to its potential for exponential acceleration in solving specific problems, quantum computing had subversive significance for cryptographic security, material design, artificial intelligence, and even national defense technology.

The Long Kingdom was not without a layout in the quantum field, and multiple national-level projects had been underway for years, achieving world-class results in certain directions (such as optical quantum and superconducting quantum), but in terms of overall system integration, logical qubit scale, and engineering reliability, there was indeed a significant gap compared to the parameters displayed by athena.

"Our quantum research needs faster, more focused, and bolder breakthroughs."

Academician Qin's gaze swept over the attendees and finally rested on Lin Shen for a moment.

"We cannot ignore or even abandon the competition in this more fundamental battlefield of quantum just because we have just seen a glimmer of hope in photonic integration."

"Walking on two legs, or even multiple legs, is the only robust strategy."

Lin Shen agreed deeply with this.

For the past two weeks, while fully pushing forward "on-chip light source integration," the next hurdle for photonic chips, he had devoted almost all his remaining energy and access to the firefly channel to the study and organization of quantum computing, especially its underlying physical and engineering bottlenecks.

He was like a greedy sponge, absorbing everything in the quantum section of the firefly knowledge base.

From the Schrödinger equation, basic concepts of superposition and entanglement, to specific physical implementations like superconducting Josephson junctions, ion trap laser manipulation, and quantum dot charge noise; from the theory of quantum error correction codes (such as surface codes) to engineering challenges like dilution refrigerators, microwave control electronics, and cryogenic filtering... the information was vast and profound, and much of it far exceeded his original knowledge framework.

But miraculously, whenever he learned a new concept or understood a key bottleneck, the "lock" phantom on the gray node labeled [Quantum Computing Theory] on the technology tree in his mind would loosen slightly, and finer branches representing different technical paths would extend from it.

Among them, the two branches representing [Superconducting Quantum Computing] and [Ion Trap Quantum Computing] were relatively brighter, obviously because these two paths were currently the international mainstream and the basis of the hybrid architecture adopted by athena, and there was the most material available on them.

However, Lin Shen's attention was drawn to a thinner, almost completely dim, and flickering branch that split from the main trunk of the [Quantum Computing Theory] node.

The end of this branch pointed to a sub-node named [Topological Quantum Computing].

Unlike superconducting, ion trap, and other methods that utilize the discrete energy levels of qubits, the theoretical basis of Topological Quantum Computing is to use topologically protected quantum states generated by braiding the world lines of quasiparticles called "Anyons" in a two-dimensional system to perform calculations.

Its greatest advantage is that, theoretically, it has extremely strong immunity to local disturbances and noise; quantum information is stored in global topological properties rather than fragile local quantum states, which might fundamentally solve the biggest problem of quantum error correction.

But this was just theory.

In reality, the stable existence and manipulation of Majorana zero modes (considered a possible carrier for realizing topological qubits), the harsh experimental conditions like extreme low temperatures and strong magnetic fields, and how to realize effective quantum gate operations... were all huge, unresolved challenges.

International research on this was still in a very basic exploratory stage, far from reaching the threshold of engineering.

Therefore, in the firefly knowledge base, there was the least amount of material on Topological Quantum Computing, mostly profound mathematical physics papers and preliminary progress reports from a few top experimental groups; the prospects were enticing but the road was dim.

Yet, Lin Shen developed an unusual interest in this dim branch.

It was not just because of its theoretical beauty and potential revolutionary advantages, but because when he focused his consciousness on it, the technology tree fed back a strange "sense of resonance."

This resonance was somewhat similar to when he first came into contact with the concept of photonic chips, but it was deeper and more obscure, as if touching some deeper rules about the essence of matter and information.

He vaguely felt that this path might be one of the "truer" ultimate forms of quantum computing that the technology tree was "inclined" toward?

Of course, this was just intuition.

He tried to deeply understand the core ideas of Topological Quantum Computing, but those abstract mathematical concepts involving topological order, braid groups, and non-Abelian statistics gave even him, with his background in condensed matter physics, a headache.

The lack of prerequisite knowledge severely hindered his "parsing" of this node.

"Need to catch up... need more systematic theoretical study, especially in the frontier fields of topological states of matter and condensed matter theory."

Lin Shen rubbed his throbbing temples and paced in the studio.

Relying solely on self-study and scattered papers in the firefly library was too inefficient.

He needed a guide, or at least a think tank that could systematically organize the frontiers and key problems in this field.

Through the firefly channel, he submitted an information request application, hoping to obtain a report on the top domestic experts, the latest research trends, and the deployment of relevant large-scale experimental equipment in the field of Topological Quantum Computing.

The application was quickly approved.

A highly condensed encrypted file was sent to his terminal.

The file showed that the Long Kingdom was not a blank slate in the field of Topological Quantum Computing.

Several top domestic theoretical physics schools and research institutes had deep accumulation in basic research directions such as topological states of matter and Majorana fermions, and had even produced internationally influential work.

In terms of experiments, institutions such as the High Magnetic Field Science Center under the Chinese Academy of Sciences and the Extreme Conditions Physics Laboratory also had some conditions for carrying out such harsh experiments.

But overall, research forces were relatively scattered, lacking the traction of large national projects oriented toward clear engineering goals like athena, and communication and collaboration between teams were not tight enough.

Attached to the end of the file was a recommended list, listing several recognized authorities in the field.

Among them, Professor Wen Zhao from Shuimu University was the top choice for theory, and Researcher Fang Zhen from the Institute of Physics of the Chinese Academy of Sciences was the choice for experiments.

Lin Shen noted down these two names.

Just then, the studio door was gently knocked.

Sun Qiming walked in with a somewhat strange expression, holding an encrypted tablet.

"Engineer Lin, an urgent notice from headquarters."

Sun Qiming handed him the tablet.

"And... a special 'gift'."

Lin Shen took the tablet, which contained a summary of the order just issued by the Chasing Light project headquarters.

The core content was: In view of the severe challenges and strategic pressure brought by athena, the superiors decided to urgently launch a quantum computing research project code-named "Jiuzhang Special Project" on the basis of the original Chasing Light project.

It aimed to concentrate forces to create a quantum computing prototype system belonging to the Long Kingdom with international competitiveness in the short term (12-18 months), responding directly to "quantum supremacy."

The Jiuzhang Special Project would fully absorb the achievements and experience of existing domestic technical routes, but required the proposal of innovative schemes with significant characteristics or potential advantages, avoiding simple following and imitation.

The original personnel of the Chasing Light project, because of their innovative ability and engineering execution shown in the field of photonic integration, were required to draw key members to participate in the initial demonstration and scheme design work of the Jiuzhang Special Project.

Lin Shen, as the current most breakthrough technical core of the Chasing Light project, was named to join the expert advisory group (temporary) for the Jiuzhang Special Project and to submit an independent analysis report on quantum computing technical paths, especially potentially subversive directions, within two weeks.

The pressure soared.

This meant he had to be distracted and go deep into the quantum field while continuing to lead the photonic chip attack, and form insightful judgments in a very short time.

"What about the gift?"

Lin Shen put down the tablet and looked at Sun Qiming.

Sun Qiming pointed to an encrypted data interface below the tablet: "Headquarters considered your increased workload and specially approved a resource."

"Through this interface, you can temporarily access a dedicated node of the national supercomputing center tianhe-3 and obtain a continuous computing resource quota equivalent to a medium-sized research group to support your theoretical simulations and scheme deductions."

"In addition," he paused, "Academician Qin personally coordinated to win you a chance for a confidential video conference with Professor Wen Zhao of Shuimu University, scheduled for nine o'clock tomorrow morning."

"Professor Wen is a leading authority in the field of domestic topological states of matter and quantum theory, but his temper... is a bit special, so you should be prepared."

Lin Shen's eyes lit up.

Supercomputing resources were a timely help, which could greatly accelerate his various simulations and calculations.

And a direct exchange with Professor Wen Zhao was exactly what he needed most right now!

This might help him quickly clear the fog in the field of Topological Quantum Computing and find the key to unlock that dim branch on the technology tree.

"Thank the headquarters for me, and thank Academician Qin."

Lin Shen said solemnly.

After Sun Qiming left, Lin Shen immediately connected the encrypted interface to his work terminal.

Massive computing resources poured in like a tide; he could run more complex photonic device simulations and try to build some simple quantum circuit models.

But the first thing he did was to use this computing power, combined with the data in the firefly knowledge base, to conduct a more in-depth and large-scale multi-physics coupling simulation of the photonic chip interface modification process he had previously optimized, hoping to find possibilities for further improving performance and reducing process sensitivity.

This was his "basic disk" and could not be relaxed in the slightest.

After dealing with the most urgent simulation tasks on the photon side, he turned his attention to quantum.

He did not immediately touch those complex topological theories, but started from the relatively familiar superconducting and ion trap paths, using supercomputing resources to run some public qubit noise models and performance simulations of simple error correction codes, to intuitively feel how severe the challenges facing current mainstream technical paths were.

The simulation results confirmed the descriptions in the literature: as the number of qubits increased, the physical qubit overhead required for error correction increased exponentially, and the requirements for gate fidelity and coherence time were despairingly harsh.

If the 512 logical qubits and ultra-high fidelity claimed by athena were true, there must be unimaginable breakthroughs in materials, cryogenic technology, control electronics, error correction algorithms, etc.

This made him feel even more that perhaps he really needed to think about changing tracks.

Late at night, the ventilation system of the underground base emitted a low, constant hum.

Lin Shen brewed a cup of strong tea, opened some of Professor Wen Zhao's recent public lecture videos and representative papers (non-core parts), and began to preview.

Professor Wen's academic style was known for being profound, sharp, and even somewhat "uncompromising"; for questioners with weak foundations or unclear logic, he was often cutting.

He had to be fully prepared to gain the most from this valuable exchange.

Looking at the thin, vigorous old man with sharp eyes like an eagle in the video, Lin Shen was full of expectation, but also had a trace of nervousness when facing a true academic authority.

Topological quantum... could this new branch, just sprouting and still very tender on the technology tree, find soil to take root in the wind and rain of reality, and eventually grow into a towering tree capable of shaking the hegemony of athena?

Tomorrow's conversation with Professor Wen might be the first step in finding the answer.