14: Chapter 14 Peeping Eyes Outside the Laboratory
The computing power of tianhe-3 surged like an invisible torrent through the virtual computing space carved out specifically for the Xuance Group.
On the screens, complex energy band structure diagrams, topological invariant values, and quasiparticle state densities simulated based on various material parameters were constantly generated and refreshed, resembling abstract and mysterious star charts.
Lin Shen had been working continuously in this secure studio for forty-eight hours, with less than eight hours of intermittent rest during that time.
The effects of the strong coffee were wearing off, and his temples throbbed faintly, yet his mind remained unusually exhilarated due to his intense focus and the constant stream of new discoveries.
The theoretical models provided by Professor Wen Zhao's team focused on several potential candidate material systems for topological superconductors, including doped topological insulators, certain two-dimensional material heterojunctions with strong spin-Orbit coupling, and artificial structures of unconventional superconductors and magnetic materials.
These models were simplified from cutting-edge tight-binding approximations or first-principles calculations, with the goal of predicting in which parameter ranges topologically protected edge states or Majorana zero modes might exist.
Lin Shen's task was to utilize the more powerful computing capacity of tianhe-3 to conduct larger-scale, higher-precision numerical scans and stability analyses on these models, searching for the "sweet spot" parameter regions that were most robust in theory and least sensitive to disorder and interference.
Progress was not smooth during the first two days. Many simulation results were either mediocre or strongly correlated with known, difficult-to-achieve extreme conditions (such as extremely low temperatures, difficult-to-control doping concentrations, or impossible ideal interfaces). This confirmed the immense difficulty of achieving Topological Quantum Computing experimentally.
But Lin Shen did not lose heart. While familiarizing himself with these quantum many-body calculation tools, he constantly adjusted his simulation strategies.
He attempted to introduce more realistic defect and fluctuation models to examine the "resilience" of topological protection; he used the limited real material data from the "Xinghai" knowledge base to constrain and calibrate theoretical parameters; he even began attempting to combine the advantageous properties of different materials (such as the strong spin-Orbit coupling of one material and the stable superconductivity of another) through virtual heterostructure designs, conducting "computational experiments."
Just as he was immersed in this high-intensity digital exploration, the studio's access control system emitted a faint beep, indicating a visitor requesting entry. Lin Shen glanced at the surveillance screen; Sun Qiming was standing outside, seemingly holding a document with a somewhat serious expression.
Lin Shen rubbed his sore eyes and stood up to open the door.
"Engineer Lin, sorry to bother you." Sun Qiming walked in, closed the door behind him, and swept his gaze over the workbench, which was cluttered with draft paper and multiple screens displaying complex charts. "The work intensity is too high; you need to take care of your health."
"I'm fine, it's at a critical stage." Lin Shen gestured for Sun Qiming to sit down. "Is something up?"
"Two things." Sun Qiming handed the document in his hand to Lin Shen. "First, this is the first-stage resource allocation plan for the Xuance Group just issued by the Jiuzhang Special Project command center. Your team members are basically confirmed."
Lin Shen took the document and scanned it quickly. In addition to He Yun, Chen Fan, and two master's students (Li Rui, Wang Xiaoyu) continuing their support, the special command center had coordinated two new members for him:
One was a young associate researcher from the National Center for Theoretical Physics, Topologist, who specialized in topological states and numerical calculations in condensed matter theory. He happened to be a grand-student of Professor Wen Zhao, possessed solid theoretical foundations, and was precisely the quantum many-body calculation expert Lin Shen urgently needed.
The other was a senior engineer from the Chinese Academy of Sciences High Magnetic Field Science Center, Shen Hong, who possessed extensive experience in physical property measurement and experimental device design under extreme conditions (high magnetic fields, extremely low temperatures). He would be responsible for converting theoretical predictions into executable experimental protocols and coordinating machine time applications for large scientific facilities.
The addition of these two members instantly fleshed out the framework of the Xuance Group. Lin Shen felt a sense of reassurance.
"And the second thing?" Lin Shen looked at Sun Qiming.
Sun Qiming's expression grew more serious. "The security department has detected some anomalies that you need to be aware of and remain vigilant about."
"Anomalies?"
"Yes." Sun Qiming lowered his voice. "Over the past week, the electronic detection system on the perimeter of the base has captured several weak signal scans of unknown origin and concealed characteristics. The target seems to be this newly activated auxiliary base, especially... the electromagnetic signal leakage from the underground research area. Although our shielding measures are very comprehensive and cannot be penetrated by conventional means, the other party has used unconventional, low-frequency, and extremely covert temporal detection techniques, likely with the intention of probing our activity patterns, energy consumption characteristics, or searching for possible shielding vulnerabilities."
Lin Shen felt a chill in his heart. "Is this aimed at the Jiuzhang Special Project? Or at me personally?"
"It's impossible to determine at the moment." Sun Qiming shook his head. "After the release of athena, international intelligence activities have clearly intensified, and all parties are trying to figure out our reactions and trump cards. Although your newly established Xuance Group has a high security clearance, there are records of personnel transfers and resource applications, which may have already attracted the attention of certain parties. Of course, it also cannot be ruled out that this is follow-up attention regarding the photonic chip achievements of the Chasing Light project."
He paused and continued, "Internal base security has been upgraded, and counter-reconnaissance measures have been fully launched. Regarding you personally, the command center suggests minimizing unnecessary outings and public activities in the near future. All communication with the outside must be through encrypted channels, and you must be careful to screen any strangers attempting to approach or inquire about your situation. Additionally, the political vetting and background checks for your team members have been completed, and they are all reliable, but in daily work, you still need to pay attention to the tiered control of information, especially regarding core theoretical models and simulation data."
Lin Shen nodded. He had long been mentally prepared that venturing into this level of competition would inevitably be accompanied by prying eyes and pressure from the shadows. He just hadn't expected it to come so quickly and so directly.
"I understand, I will be careful." Lin Shen said solemnly.
"Also," Sun Qiming added, "Engineer Shen Hong will arrive at the base to report for duty tomorrow morning. As for researcher Topologist, because he still has some finishing work on hand, he will likely arrive in about three days. The command center hopes you can integrate quickly and produce the first phase analysis report for the Xuance Group, to secure resources for potential subsequent experimental verification."
After seeing Sun Qiming off, Lin Shen sat back down at the workbench, but his mood could no longer be completely calm. The prying eyes outside the lab hung over him like an invisible haze. He knew that from this moment on, he would not only have to charge to the forefront of technology but also be on guard against arrows from the shadows at any time.
He took a deep breath and forcibly pulled his attention back to the screen. Now, panic or anger would be of no use. Only by producing tangible, convincing results could he offer the best defense and counterattack.
His gaze fell on a set of simulation results he had just completed. This was the interface state energy spectrum calculated after he attempted to virtually stack a known two-dimensional topological insulator material (bismuth selenide) with an unconventional superconductor (niobium nitride) into a heterostructure. At a certain specific interlayer coupling strength and Fermi level position, the simulation showed an extremely narrow but clear, almost flat energy band passing through the Fermi energy, accompanied by a non-trivial topological Chern number.
This feature was very similar to the topological superconducting edge states that theoretical predictions suggested might host Majorana zero modes!
Furthermore, the simulation showed that this "sweet spot" parameter window had a certain tolerance for interlayer lattice mismatch and a small amount of disorder, unlike many previous models which were fragile.
Lin Shen's heart skipped a beat. This might be a clue worth digging into!
He immediately pulled up the "Xinghai" knowledge base to retrieve the current research status on the actual growth, characterization, and heterostructure preparation of the two materials, bismuth selenide and niobium nitride. The results showed that both materials were hot topics in current condensed matter physics research, and each had mature molecular beam epitaxy (MBE) growth techniques. However, combining them with high quality and precisely controlling the interface was rarely reported publicly at home or abroad, placing it at the very forefront of the cutting edge.
"If this theoretical prediction holds..." Lin Shen thought rapidly, "then the next step is to design an experiment to verify it. We will need extremely high-quality samples, and we will need to conduct precise electrical transport (such as quantized conductance) or scanning tunneling microscopy (STM) measurements under extremely low temperatures and high magnetic fields to search for evidence of the existence of Majorana zero modes..."
This was exactly why he needed Engineer Shen Hong's experience with extreme-condition experiments, as well as his ability to coordinate large scientific facilities such as the High Magnetic Field Science Center and low-temperature physics laboratories.
Lin Shen suppressed his excitement and began to organize these preliminary findings, preparing to formulate a more specific research plan for tomorrow's team meeting and the arrival of the new members. He wanted to transform this faint glimmer of light excavated from the digital world into a clear and powerful action plan.
Outside the window, the shelter forest was reduced to dark silhouettes in the night, and the city lights in the distance were blurry and remote, as if seen through a layer of frosted glass. This underground studio seemed like an isolated island, yet because it was connected to the nation's most cutting-edge technological network and the fiercest international competition, it stood at the center of the storm.
Prying eyes flickered in the dark, and Lin Shen and his team were about to light the first lamp in the exploration of the Topological Quantum Computing world under the gaze of these eyes.
No matter what this light might attract, they had no other choice but to move forward.