A Cosmic Symphony. The Workshop that Explains the Universe with String Theory

With the enthusiastic participation of the Chinese audience, Spanish students, and people interested in physics and scientific dissemination, the workshop Sinfonía cósmica [Cosmic Symphony), organized by UNAM-China in collaboration with the Cervantes Institute in Pekin, was held. The event took place at the Rincón UNAM (UNAM Corner) of the Antonio Machado Library. 

The workshop was led by physicist doctor Ricardo Espíndola Romero, postdoctoral researcher at the Institute for Advanced Study, Tsinghua University (IAS-THU) and a graduate from UNAM’s Faculty of Science. Dr. Espíndola—acknowledged for his work in theoretical physics—accessibly explained the fundamentals of string theory, a scientific proposal that aims to unify general relativity and quantum mechanics to understand the mysteries of the universe. 

The conceptualization for the workshop was developed by UNAM-China as a way to promote digital content at the Rincón UNAM and disseminate Spanish in scientific topics. 
 
SCIENCE AND MUSIC: AN INTERDISCIPLINARY CONNECTION
To illustrate key concepts, Espíndola established a link between string theory and music with the support of Luo Xiran, a player of the pipa, a traditional Chinese instrument [see UNAM International 6, p. 100]. This approach made it possible to translate abstract ideas from physics into tangible sensory experiences, facilitating the audience’s comprehension. 

According to Espíndola, string theory proposes that the fundamental particles of the universe are not dots, but small strings vibrating in tiny dimensions. Each string vibration corresponds to a specific particle with a mass and properties of its own, similar to how a string on a musical instrument generates unique sounds. Strings can vibrate in different ways, and each vibration pattern corresponds to a different particle, like musical notes. For example, one vibration could correspond to an electron and another to a photon. 

“Strings produce more elaborate sounds when they interact, like when several musical notes combine in a melody. These constant interactions are what make the universe a true cosmic symphony,” explained the researcher. 

Luo Xiran translated this vision into her musical interpretation by using simple tones that evolved into more complex melodies to reflect the interactions between particles described by the theory. 

The researcher explained that two of the fundamental backbones of modern physics are general relativity and quantum mechanics, which describe the behavior of the universe at different scales but are not compatible with each other. Formulated by Albert Einstein in 1915, the Theory of General Relativity describes gravity and the way space-time behaves at large scales: stars, galaxies, and the universe as a whole. 

Quantum mechanics, on the other hand, describes the world of the smallest things: atoms, subatomic particles, and fundamental forces at microscopic scales. General relativity and quantum mechanics use incompatible mathematical languages. The former is deterministic and treats space-time as a somehow smooth continuous structure. The latter, on the other hand, is probabilistic and operates in a discrete and fluctuating world. 

String theory arose as an attempt to unify general relativity and quantum mechanics into a single coherent theory, known as the “Theory of Everything”. 

What is revolutionary is that the string theory naturally incorporates gravity by predicting the existence of a particle called the graviton, which is responsible for transmitting gravitational force. 

Wave and particle concepts are fundamental in physics and help us understand how light, matter, and other entities behave in the universe. Wave-particle duality is a revolutionary concept in quantum physics that can tell us that certain things such as light and subatomic particles (electrons, protons, etc.), can behave as waves as well as particles, depending on the way we observe them. 

Moreover, string theory requires the existence of extra dimensions beyond the four we perceive (three spatial and one temporal). According to this theory, the universe would have 10 or 11 dimensions, depending on the version of the theory. 

Although it has not yet been experimentally proven, it represents one of the most promising proposals for the understanding of the mysteries of the universe at all scales. 

In the Sinfonía cósmica workshop, the relationship between string theory and music became clearer to attendees when Espíndola explained that interactions between particles—like collisions that generate new particles—can be understood as a more complex musical process. 

“These interactions happen frequently in nature, so we can imagine the universe as a symphony full of collisions and interactions between strings,” he explained. 

Espíndola described how in string theory, every particle in the universe is associated with a vibrating string. These strings can vibrate in multiple ways and each vibration pattern corresponds to a distinct particle with a specific mass, determined by the frequency of the vibration. He stated that what we call music is an analogy for the sounds that strings would produce when vibrating at different frequencies. 

Luo Xiran adapted this vision to her musical interpretation. After consulting with Espíndola, she integrated specific techniques into the pipa performance to illustrate the vibration of strings through simple tones that evolve into more complex melodies, emulating particles that interact and create new patterns in nature. She used techniques that highlighted overtones, allowing attendees to connect the abstraction of theoretical physics with the tangible experience of music. 

One of the highlights was when Luo Xiran performed a pipa piece symbolizing the battle between two armies known as the Battle of Red Cliffs at the end of the Han dynasty (years 208-209) by using different musical scales. One of the scales represented the victors while the other evoked the vanquished. 

This musical piece sought to illustrate the concept of the “holographic dictionary” explained by Espíndola, which posits the existence of a theoretical framework that could translate the laws of one theory into the other. This approach is based on the hypothesis that the different physical theories describe the same fundamental phenomena but have not been fully connected due to differences in their mathematical and conceptual approaches. 
 
TRANSLATION AS A COMMUNICATIVE BRIDGE
The workshop was conducted in Chinese and Spanish with interpretation by Wang Zhen, a graduate student at Beijing Foreign Studies University and an intern at UNAM-China. His work was acknowledged by the speakers and the organizers since he did not only interpret the concepts in both languages but also managed to synthesize the musical and physics terms into understandable words for the audience. 
 
HIGH-LEVEL SPEAKERS 
Due to his academic achievements, Ricardo Espíndola Romero was selected to pursue a postdoc under the Shuimu program, hence becoming the first Ibero-American physicist to be accepted into said program at Tsinghua University, one of the most prestigious universities in China. 

Ricardo focuses his current research on holographic correspondence, studying how to reconstruct semiclassical space-time from quantum entanglement of dual states to gravity. He won the national competition “Estancias de verano teóricas en el extranjero en física de altas energías” [Theoretical summer abroad fellowships in high energy physics], which allowed him to carry a fellowship out at the International Center for Theoretical Physics (ICTP) in Italy. Later, he stayed at the String Theory Group of the University of Southampton in the United Kingdom. He completed his PhD studies at the University of Amsterdam under the mentorship of Jan de Boer, one of the foremost theorists in string theory and quantum gravity. 

Luo Xiran is a principal pipist of the China Conservatory Orchestra. She holds a master’s degree in pipa performance from the Central Conservatory of Music. Luo has performed at venues such as the National Centre for the Performing Arts, the Forbidden City in Beijing, the Great Hall of the People, and the Beijing Concert Hall. She has received various awards such as the Gold Award in the Senior Division of the Traditional Chinese Instrumental Music Exhibition “Yungang Cup” in 2023. 

The workshop—with a limited capacity of twenty people—took place in the Rincón UNAM, a space in an intimate and participative atmosphere. It did not only make accessible a complex theory but also generated an impact on the attendees, who learned concepts of the universe such as the cosmic symphony, connecting science, Chinese music, and the Spanish language. 

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