In the quantum gravity laboratory three hundred meters underground at the String Light Research Institute, the air seemed to have congealed into some kind of transparent crystal. Yue'er stood before the main console, her gaze tightly fixed on the cylindrical vacuum chamber behind three layers of bulletproof glass. Named the "Spacetime Probe," this device had its internal temperature lowered to minus 273.149 degrees Celsius—only 0.001 degrees above absolute zero. At such extreme low temperatures, the quantum properties of matter began to manifest at visible scales.
The laboratory walls were covered with thick layers of lead and mu‑metal, intended to isolate all external interference. On the surface, people could sense the flow of wind, changes in temperature, even the Coriolis force from Earth's rotation; but here, even cosmic rays were filtered out, and time seemed to flow at a different rhythm. The experiment Yue'er designed aimed to directly observe quantum fluctuations in spacetime itself—those microscopic wormholes, quantum foam, and virtual particle pairs of gravitons that continually emerge and annihilate at the Planck scale.
At the center of the vacuum chamber, three micron‑scale superconducting gyroscopes were suspended. Made of niobium‑titanium alloy with a surface coating of single‑layer graphene, they had entered the superconducting state under liquid‑helium temperatures. These gyroscopes were not fixed by mechanical bearings; rather, they levitated within the vacuum through precisely controlled magnetic fields, completely detached from any physical contact. Each gyroscope surface was etched with nanoscale gratings that modulated reflected laser signals when the gyroscopes rotated, achieving an accuracy of 10⁻²⁰ radians—equivalent to observing the rotation of a single hair on the Moon from Earth.
"Activate the data‑acquisition system." Yue'er's voice sounded exceptionally clear in the silent laboratory. Her fingers entered a series of commands on the control panel, activating the twelve laser interferometers surrounding the vacuum chamber. The laser beams from these interferometers intertwined within the vacuum chamber to form a light‑net, precisely monitoring the spatial positions and orientations of the three superconducting gyroscopes.
The experiment's core idea originated from a quantized interpretation of Mach's principle. In classical physics, Mach's principle posits that an object's inertia is not an inherent property but a comprehensive result of all matter in the universe acting upon it. An object's mass, in a sense, is the consequence of the entire universe's influence. Yue'er extended this idea to the quantum realm: at the Planck scale, spacetime itself is no longer a smooth continuum but a discrete structure connected by quantum entanglement. The properties of a local inertial frame—that is, a free‑fall reference frame—are determined by the quantum correlations of all matter distribution in the universe.
If this theory were correct, then even in a vacuum completely shielded from external influence, the superconducting gyroscopes would not remain completely still. Quantum fluctuations of spacetime itself would produce observable effects on the gyroscopes through Mach's principle. Specifically, due to quantum fluctuations in matter distribution at the edge of the universe, local inertial frames would undergo minute changes, causing the suspended gyroscopes to exhibit spontaneous precession—as if an invisible hand were gently nudging them to rotate.
"Temperature stabilized at target value." An assistant researcher reported, "All superconducting gyroscopes have entered stable levitation state."
Yue'er nodded, her gaze shifting to the data monitor. The screen displayed real‑time orientation data for the three gyroscopes; currently they maintained remarkable stability, with fluctuations within measurement‑error margins. But this was merely the calm before the storm. According to theoretical predictions, when quantum fluctuations of spacetime became sufficiently intense, they would produce detectable precession signals on the gyroscopes.
Time passed minute by minute, the laboratory filled only with the low hum of operating instruments. Yue'er recalled the countless technical hurdles overcome in constructing this laboratory: how to manufacture perfectly spherical micron‑scale superconducting gyroscopes, how to maintain stable magnetic levitation under extreme low temperatures, how to design a sufficiently sensitive laser‑measurement system... Every detail embodied years of effort from the team.
Suddenly, an anomalous pulse appeared on the data monitor. Although it quickly returned to baseline level, this was enough to tense the atmosphere throughout the laboratory.
"Is it noise?" an assistant researcher whispered.
Yue'er quickly pulled up detailed data of the pulse and shook her head. "The pulse's spectral characteristics do not match any known noise source. Continue monitoring."
Over the next three hours, similar pulses appeared seven more times. Each lasted from a few milliseconds to several tens of seconds, with varying intensities. Most surprisingly, the pulse signals from the three gyroscopes showed high correlation—when one gyroscope detected a signal, the other two would respond within an extremely short time.
"Signal propagation speed exceeds light speed." A data analyst reported a shocking result. "Based on the positions of the three gyroscopes and the time differences of signal arrival, the propagation speed of this disturbance is at least ten times the speed of light."
This result plunged the laboratory into silence. If the data were genuine, then what they observed could not be any known physical phenomenon. According to special relativity, no information or energy can propagate faster than light.
Yue'er pondered a moment, then called up the theoretical model on the console. "In quantum‑gravity theory, spacetime itself may be non‑local." She explained to the team. "Two points that are distant in classical spacetime may be directly correlated at the quantum level. What we observe may be non‑local correlations within the microscopic structure of spacetime."
To verify this conjecture, she instructed the system to begin recording detailed characteristics of each pulse, including its spectral composition, polarization properties, and phase relationships among the three gyroscopes. Data flooded in like a tide, quickly filling the entire storage array.
At two o'clock in the early morning, when most people were already exhausted, a sustained and stable signal suddenly appeared on the main monitor. The three superconducting gyroscopes began synchronized precession, their motion trajectories exhibiting the elegant characteristics of Larmor precession, as if rotating within some invisible magnetic field.
"Precession frequency is steadily increasing." The assistant researcher's voice trembled with excitement. "Already exceeding noise level by two orders of magnitude."
Yue'er immediately activated high‑speed data‑recording mode. On the screen, the gyroscopes' precession trajectories grew increasingly clear, forming a perfect conical surface. Most astonishingly, this precession pattern was not fixed but slowly evolving, as if responding to some invisible force.
"Is it gravitational waves?" someone asked.
"No." Yue'er denied. "If it were gravitational waves, the precession patterns of the three gyroscopes should be consistent. But now they show different precession axes and frequencies."
She quickly ran a data‑analysis program, comparing the observed precession patterns with theoretical predictions. The results indicated that these precessions highly matched a special mode of spacetime quantum fluctuations—possibly the generation and annihilation of microscopic wormholes, or quantum oscillations of graviton condensates.
"We may need a new theoretical framework to explain these data." Yue'er said softly. Traditional quantum‑gravity theories, while predicting quantum fluctuations of spacetime, generally considered these effects too weak to be observable at laboratory scales. Yet the signal strength they now observed exceeded theoretical predictions by several orders of magnitude.
Just then, the laboratory door was gently pushed open. Xiuxiu stood at the doorway, her face showing concern. "I heard you have been working continuously for forty hours." she said. "Do you need to rest?"
Yue'er shook her head, displaying the recently recorded data to Xiuxiu. "We may have discovered the microscopic structure of spacetime."
Xiuxiu examined the data carefully. As an expert in biological computing, she immediately recognized the significance of these discoveries. "If spacetime indeed possesses such structures at the quantum level, it may have profound implications for quantum processes in biological systems."
The two female scientists stood before the console, jointly gazing at those elegant curves on the screen. Within those precession trajectories lay the deepest mysteries of the universe—the fabric of spacetime itself.
"Adjust the interferometers' sensitivity." Yue'er commanded. "I want to see what fine structures these signals reveal at higher resolution."
When the interferometers' sensitivity was boosted to the limit, a breathtaking scene appeared on the screen: the precession signals were not smooth and continuous but composed of countless discrete pulses, each lasting on the order of milliseconds, with intensity distributions exhibiting typical fractal characteristics.
"Is this... the atomic structure of spacetime?" an assistant researcher marveled.
Yue'er did not immediately answer. She performed a fast Fourier transform, discovering that the signal spectrum showed distinct peaks at a specific frequency. The energy scale corresponding to this frequency was precisely near the Planck energy.
"We may have truly touched the quantum structure of spacetime." she whispered, her voice carrying a hint of irrepressible excitement.
Over the next several hours, the team recorded more types of signals. Some manifested as sudden orientation jumps, others as slow periodic oscillations, and still others displayed chaotic characteristics. Most perplexingly, certain signals seemed to exhibit memory effects—when a particular pattern of signal appeared, the probability of similar patterns reappearing significantly increased.
"Spacetime has memory?" Xiuxiu proposed a bold conjecture.
Yue'er contemplated this possibility. In loop‑quantum‑gravity theory, spacetime is indeed described as spin networks, where each process leaves "traces" in the structure of spacetime. If what they observed were truly such effects, this meant that spacetime at the microscopic level indeed possessed some form of memory capability.
When the first glimmer of dawn penetrated the simulated windows of the underground laboratory, the experiment had continued for a full forty‑eight hours. The volume of data collected by the team already surpassed the sum of all previous quantum‑gravity experiments.
Yue'er finally agreed to temporarily rest. Before leaving the laboratory, she checked the system's operational status one last time. The three superconducting gyroscopes still rotated quietly within the vacuum chamber, recording the very "breathing" of spacetime.
"We have established a window." Yue'er said to Xiuxiu. "A window to peer into the essence of quantum spacetime."
Xiuxiu nodded, her gaze still fixed on those beautiful data curves. "This reminds me of the helical structure of DNA. At completely different scales, nature seems to favor using some similar language."
On the way back to the office, Yue'er pondered this problem continuously. Perhaps indeed there existed some deep connection between the quantum structure of spacetime and the molecular structure of life. And this might be the next direction to explore.
She sat at her desk and began writing the experimental report. In the summary section, she wrote: "Today's experiment not only verifies the correctness of the quantized Mach principle but, more importantly, opens a door to the world of quantum spacetime. For the first time, we are able to directly 'touch' the microscopic structure of spacetime, observing its fluctuations and evolution. This is not only a triumph for theoretical physics but also a milestone for experimental technology."
Writing this, she paused, adding a personal reflection: "When we can observe quantum fluctuations of spacetime, our dialogue with the universe enters an entirely new stage. This is no longer distant observation but intimate exchange. In this process, we are not only exploring the mysteries of the universe but also understanding our own place within it."
This report later became a classic document in the field of quantum‑gravity research, and the specific quantum‑fluctuation patterns they observed were named "Yue'er Oscillations," becoming an important tool for probing quantum‑spacetime structures. But at this moment, for Yue'er, the most important thing was that they had finally found a method to directly listen to the deepest rhythms of the universe.