When a light wave is reflected at the interface between two semi-infinite media,the relative phase between the reflected and incident amplitudes is a fundamental optical effect.Another fundamental phase relation arises in a symmetric beam splitter between its reflection and transmission amplitudes.Both effects originate from the phase structure of wave scatter-ing,although their underlying connection is not always clearly understood.As a pedagogical investigation,this paper systematically analyzes these phase relations using simple one-dimen-sional potential models in quantum mechanics and provides intuitive physical explanations.For a symmetric square barrier,the reflected and transmitted amplitudes necessarily differ in phase by±π/2,with the reflection phase referenced at the interface on the incident side and the transmission phase referenced at the interface on the exit side.The result is further ex-tended to general symmetric barriers,for which the detailed form of the barrier determines only whether the phase difference is+π/2 or-π/2.The role of this phase structure in the second-order interference of two identical particles is then examined.Through this sequence of analysis,half-wave loss at a reflecting interface,the phase relation in a symmetric beam split-ter,and multiparticle quantum interference are incorporated into a unified wave-scattering framework.This treatment provides a useful pedagogical reference for related topics in quan-tum mechanics and optics courses.
The Experimental Physics Teaching Center of the Department of Physics at Tsing-hua University has carried out the improvementand teaching practice of a series of fundamen-tal physics experiment courses based on"integration of science and education"and a"modular platform".This paper elaborates on the overall design philosophy and teaching practices.Ef-forts have been strengthened in building research-oriented and challenging experimentssuch as coaxial photonic crystals and rotating fiber-optic interferometers.Open and transparent teach-ing platforms combining general-purpose instruments with self-developed modular has been a-dopted.A progressive"foundation-comprehensive-research"teaching model has been imple-mented to promote personalized teaching.Teaching practice shows that the courses have stim-ulated students'interest in learning and achieved positive results.
The Numerical Simulation Experimental Physics(NuSEP)platform has been in op-eration for more than two years since its launch in 2024.The most consequential development during this period has been the profound and structural transformation of education driven by arti-ficial intelligence,whose breadth and depth have far exceeded expectations.Against this background,this paper examines the development trajectory and application practices of the NuSEP platform,summarizes the experience gained and lessons learned,and discusses its future directions.
Against the backdrop of the rapid development of artificial intelligence,this paper points out the historical inevitability of exploring the long-term development trend of educa-tion and emphasizes that AI's influence on education is deepening continuously.In the future,AI will become the core leading force in education,and human teachers need to seek a path of symbiosis with AI.Combining Geoffrey Hinton's viewpoints with the national action plan for the in-depth implementation of the"AI Plus"initiative,the paper expounds the inevitability of human society's development of AI and the synchronization between the intellectualization of China's education and the construction of an education power.It corely analyzes AI's impact on the underlying logic of education:driven by their intellectual curiosity,students can com-plete the learning process from total ignorance to profound understanding through continuous interaction with AI,which will lead to the gradual replacement of education's knowledge-im-parting function by AI,and the core status of ability cultivation will also be weakened in the long run,thus bringing about qualitative changes to many elements of the traditional educa-tional model.As the general introduction to a series of papers,this paper clarifies the logical framework for the analysis of four dimensions,namely Future Teachers,Future Classrooms,Future Schools and Future Learning Centers,and the series will explore these four dimensions in the progressive order from the micro to the macro and from the partial to the whole,laying a theoretical foundation and providing a framework guide for the subsequent four studies.
The independent cultivation of top-notch innovative talents in basic sciences,partic-ularly in physics,is a critical factor determining China's technological competitiveness and long-term development.However,current talent cultivation faces multiple deep-rooted chal-lenges,including short-termism,exam-oriented education,cultural traditions that inhibit in-novation,hindered international exchanges,and the impact of artificial intelligence,which ur-gently call for systematic responses at both conceptual and institutional levels.This report summarizes the practical experiences of Tsinghua University's Top-notch Talent Program from Phase 1.0 to 2.0.It analyzes the current state of national talent cultivation,the contem-porary response to"Qian Xuesen's Question,"the characteristics of China's scientific pro-gress,and the in-depth reform of university teaching in the age of artificial intelligence.It also examines the deep-seated issues faced by physics top-notch talent training bases in talent culti-vation,including domestic and international social environments,the spiritual and intellectual dimensions of teachers and students,and artificial intelligence,and puts forward several guid-ing suggestions.This paper reproduces Academician Zhu Bangfen's entire report on cultiva-ting future-oriented original innovative talents centered on the core values of"independent spirit and free thought."
This paper presents a refined teaching framework for Tsinghua University's Modern Physics Laboratory course,addressing several common problems in university physics labora-tory teaching,including an emphasis on experimental operation over design,results over process,and details over broader scientific perspectives.Guided by national talent-develop-ment strategies,Tsinghua University's educational philosophy,and students'future academic and professional needs,the course establishes four core objectives:broadening horizons,building solid foundations,learning to practice,and understanding innovation.To implement these objectives effectively,the teaching team developed a refined and differentiated instruc-tional framework consisting of three major components.First,frontier-oriented experimental chains in condensed matter physics,quantum physics,and optics were established to form a longitudinal framework that reflects academic and technological development.Second,three flexible learning modes were introduced to accommodate students with different backgrounds:a basic mode with six conventional experiments,a guided N+X extended-research mode,and an advanced mode centered on one independent experiment;a process-based assessment sys-tem emphasizing students'growth gains was also implemented.Third,a supportive hard-ware-and-software system was established,including a powerful digital platform,multidimen-sional communication channels,and a flexible equipment pool for exploratory learning.Two representative teaching cases involving quantum-computing exploration and saturated-absorp-tion spectroscopy design illustrate how students are guided from passive operation toward ac-tive inquiry and how an experimental"designer's perspective"is cultivated.Teaching practice indicates that the establishment of these objectives and the implementation of the framework promote students'transition from"operators"to"designers"and help enhance their scientific literacy and innovative capability.
Particle physics experiments have long research cycles and high barriers to entry.Limited human resources make it difficult to fully explore and analyze large volumes of colli-sion data.Agents based on large language models can write code,retrieve literature,and car-ry out multi-step analyses,offering an opportunity to address this challenge.This article fo-cuses on the Just Furnish Context(JFC)agent framework and examines results produced by the framework,including the CMS H→τ+τ-signal-strength measurement and the ALEPH Lund jet-plane density measurement,as well as their implications for particle physics re-search.It also summarizes the framework's current limitations and discusses prospects for benchmark-dataset construction,data processing at next-generation large-scale scientific facili-ties,and the training of future physicists.
This paper reviews the research progress of the research team in the Department of Physics,Tsinghua University,concerning the design,development,and application of high-temperature superconducting(HTS)microwave filters.The current state of HTS microwave filter research is presented,highlighting the team's development efforts in narrowband,wide-stopband,dual-band,triple-band,and broadband HTS filters.Furthermore,the practical ap-plication of HTS filters in mobile communication base stations is discussed.
Abstract Artificial intelligence (AI) and physics are entering a new stage of deep interdisciplinary integration. Physics has long provided foundational ideas for AI, including symmetry, statistical mechanics, and quantum theory, while continuing to inspire new model architectures, learning principles, and computational paradigms. At the same time, as AI systems become increasingly complex, their internal mechanisms, collective behavior, and emergent dynamics are becoming new objects of interest and investigation in physics. In this Perspective, we introduce Physics-first AI, a research paradigm that regards AI as a complex information-processing system embedded in the physical world and seeks to understand, design, and build intelligent systems from fundamental physics principles and modes of reasoning. Physics-First AI aims to provide a common foundation for model architectures, training mechanisms, computational processes, and reasoning paradigms through a unified physics perspective. We trace the historical interplay between physics and AI and discuss how structure priors, statistical mechanics, quantum theory, and physics reasoning may together shape the next generation of intelligent systems. We further examine how this emerging paradigm could reshape physics education and the training of interdisciplinary researchers in the AI era. Physics-First AI offers a route toward a physics-grounded theory and design framework for next-generation intelligence, opening new opportunities for scientific AI, autonomous scientific discovery, and ultimately artificial general intelligence.
The Franck-Hertz experiment,a landmark experiment in the history of modern physics,plays a significant role in undergraduate laboratory courses for elucidating atomic structure models.This paper presents an improved design for the Franck-Hertz experiment,encompassing six aspects:integration of historical context,automated data acquisition,design of experiments targeting high-excitation states,fostering of team collaboration,training in scientific software usage,and progressive formulation of thought-provoking questions.With these enhancements,students are relieved from the burden of tedious manual data recording,thereby freeing up time to substantially expand and deepen the experimental content.In addi-tion to maintaining a balance between theoretical instruction and hands-on training,the re-vised approach further cultivates scientific inquiry skills and reinforces basic competencies in scientific literacy.This reform aligns with the general-education philosophy underlying experi-mental physics teaching at Tsinghua University.
Quantum secure direct communication is a quantum communication technology that uses quantum states as carriers to transmit information securely and directly,first proposed by a team at Tsinghua University in 2000.Quantum communication broadly refers to informa-tion transfer processing tasks accomplished through the transmission of quantum states,which can be categorized into three types based on the content transmitted:quantum key dis-tribution for transmitting random numbers,quantum secure direct communication for trans-mitting classical information,and quantum teleportation for transmitting quantum informa-tion.After more than two decades of development,quantum secure direct communication has matured and entered practical application:a theoretical framework tailored for scenarios with high loss,high noise,and stringent security requirements has been established;experimental demonstrations of quantum direct communication in optical fibers and free space have been completed;three milestone systems for quantum secure direct communication at the metropol-itan,intercity,and network levels have been built;and successful trials have been conducted in various scenarios such as 5G private networks and banking applications.Quantum secure direct communication offers multiple applications:it prevents information leakage by detecting eavesdropping,ensuring information security;identifies exposed locations by monitoring sur-veillance activities,providing technical support for preventing targeted eliminations and safe-guarding commanders'personal safety;and detects intrusion and tampering behaviors,offer-ing novel protection for cybersecurity.Currently,quantum direct communication has been in-corporated into relevant planning documents in China,the European Union,and the United States,and is undergoing rapid development.This article briefly outlines the historical devel-opment,fundamental principles,research advancements,and future prospects of quantum di-rect communication.
Convolutional neural networks are widely used in tasks such as image recognition due to their excellent performance in two-dimensional data processing.To address the limited AI computing power under the traditional digital integrated circuit computing architecture,this study designs an optical convolution system based on a microlens array.Utilizing the ul-tra-high-speed and high-parallelism characteristics of optical computing,it achieves convolu-tion computation based on the principles of geometrical optics.The system loads image infor-mation and convolution kernels using a spatial light modulator,segments the light field through a microlens array,modulates the segmented sub-regions in parallel using the convolu-tion kernel,and finally converges through the imaging optical path to achieve summation,thus completing the convolution computation in optical space.This study presents the imple-mentation principle of the optical convolution system based on a microlens array,designs the experimental optical path,and proposes implementation methods for key technologies such as system calibration,convolution kernel implementation,and image post-processing.Experi-mental results show that the system possesses basic imaging performance and the ability to implement complex feature operators such as Gaussian operator,Gradient operator,and Laplacian operator.Limited by device accuracy,the system still has errors caused by aberra-tions and diffraction.It can provide verification for the feasibility of optical convolution schemes based on geometrical optical architecture in image preprocessing tasks.
Nuclei are not bags of static balls.Most protons and neutrons move under the over-all nuclear environment,but a small fraction can form fleeting close-range partners and carry unusually large momenta.These short-range correlations cannot be photographed directly.Instead,they leave statistical clues in the high-energy gamma-ray spectrum emitted at the ear-liest stage of a heavy-ion collision:faster neutron-proton encounters are more likely to produce energetic gamma rays,hardening the spectral tail.A recent 124Sn+124Sn experiment at 25MeV per nucleon used this idea,together with transport-model comparisons,detector calibration,and background checks,to infer that about 20％of nucleons in 124Sn belong to short-range-correlation-related high-momentum components.The result provides a complementary gam-ma-ray route for studying short-distance motion inside nuclei.
While AI shows great potential in empowering physics experiments,the highly in-novative and rapidly iterating nature of these experiments poses challenges for traditional Large Language Models(LLMs).Reasoning on specific methods typically requires full-con-text injection of local knowledge bases,resulting in excessive context consumption and high inference costs.This study proposes an intelligent agent framework for physics experiments integrating dynamic context-aware management and collaborative reasoning.Adaptable to ex-isting LLMs,the framework dynamically extracts and injects high-value information into the context,significantly reducing inference costs and improving efficiency without compromising reasoning quality compared to full-context methods.By supporting rapid secondary develop-ment and diverse scenario adaptation,the framework effectively overcomes computational and cost bottlenecks,offering an efficient and flexible paradigm for the automation and intelligent transformation of physics experiments.
To address structural problems in knowledge construction and the coordination of educational functions in the University Physics curriculum for science and engineering students at our university,this study,oriented toward the needs of emerging engineering education,constructs a three-stage progressive"Big Physics"educational framework integrating digitally empowered intellectual development,value guidance,and practice-driven competence cultiva-tion.Specifically,the framework digitally restructures the core course to strengthen students'scientific thinking and problem-modeling abilities;promotes coordination among related cour-ses and the deep integration of curriculum-based ideological and political education to align val-ue guidance with University Physics teaching;and establishes an integrated practice platform linking theory,experimentation,and research to facilitate the application and transfer of physics knowledge in engineering contexts.Teaching practice shows that this framework opti-mizes the logical structure of basic University Physics teaching and enhances the coherence,systematicity,and sustainability of the educational process.
The merging of gravity and the gauge principle has been a central thread in the cen-tury-long exploration of theoretical physics ever since the birth of general relativity.Taking the perspective shift from the"geometric paradigm"to the"matter paradigm"as its guiding thread,this paper systematically traces the two major stages of this merging process.The first stage takes the gauge principle as its starting point,passing through Utiyama's local Lorentz gauge theory,Sciama's spin-torsion coupling,Kibble's Poincaré gauge gravity,and culminating in the Riemann-Cartan spacetime geometry and gauge field theory framework es-tablished by Hehl and others,thereby profoundly revealing the intrinsic connection between the gauge principle and spacetime gravity.Nevertheless,this stage consistently follows the traditional paradigm of"starting from spacetime geometry."The second stage,marked by the gravitational quantum field theory proposed by one of the present authors,realizes a funda-mental paradigm shift:the gauge symmetry SP(1,3)corresponding to the spin of elementary particles is established as an independent and primary intrinsic symmetry of the fundamental building block.From this,entirely new structures such as biframe spacetime and a noncom-mutative,fiber-bundle-like gravitational gauge spacetime emerge,enabling gravitational dy-namics to be naturally derived from the basic principles of quantum field theory and breaking through the framework limitations of traditional curved spacetime geometry.This paper sys-tematically expounds the historical trajectory,core physical ideas,key mathematical struc-tures,and characteristics of field equations of the two major stages,compares and analyzes their essential differences and internal connections,and elucidates the theoretical self-consis-tency of constructing the generalized standard model and achieving a unified description of the four fundamental interactions within the framework of gravitational quantum field theory.
At the 2025 National Conference on Fundamental Physics Education in Higher Edu-cation,Academician Guo Guangcan of the University of Science and Technology of China de-livered a plenary report entitled"The Current State of Quantum Computing".He provided a systematic exposition covering the developmental context,computational advantages,research and development obstacles,global progress,phased development,and future directions of quantum computing.He clearly identified quantum computing as a core disruptive technology capable of breaking through the physical limits of classical information technology,whilst also outlining current technical bottlenecks and the landscape of domestic and international devel-opment.The report began by noting that classical information technology is based on classical physics and,constrained by Moore's Law,faces physical limits on computational power.As chip manufacturing processes approach the microscopic scale and Moore's Law ceases to hold,classical computational power will reach a bottleneck,giving rise to quantum information technology.As the most disruptive branch of quantum technology,quantum computing ex-hibits exponential growth in computational power increasing by 2N as the number of qubits in-creases,thereby fundamentally breaking through the performance ceiling of classical compu-ting.The underlying logic behind quantum computational power surpassing that of classical computing stems primarily from two unique characteristics of the quantum world:uncertainty and non-locality.Classical physics adheres to determinism and locality,whereas in the quan-tum world,the physical quantities of quantum objects follow a probability distribution,and entangled particles can exhibit instantaneous correlations and changes even when they are ex-tremely distant from one another and do not interact.The basic unit of quantum information is the qubit,which exists in a superposition of quantum states.N qubits can carry 2N classical bits of data,and a single operation can act simultaneously on all data degrees of freedom,cre-ating a natural capacity for parallel computation.Quantum entanglement provides support for quantum algorithms,enabling the computational advantage of parallel processing to be trans-formed into actual information processing efficiency.This is the physical root cause of why quantum computing power far exceeds classical computing.The report highlights two core ob-stacles in the development of quantum computers:firstly,the fragility of quantum states and their susceptibility to decoherence,whereby the macroscopic environment rapidly disrupts quantum superposition and entanglement,causing them to degrade into classical states;sec-ondly,insufficient precision in quantum manipulation,making it difficult to achieve the pre-cise preparation and control of qubits.Theoretically,solutions such as fault-tolerant quantum error-correcting codes,quantum error avoidance,and dynamical fault tolerance can address the aforementioned problems.Artificial intelligence(AI)can empower quantum computing by reducing the number of physical qubits required for encoding,optimising operational schemes,and enhancing measurement accuracy,thereby becoming a key driver of technological break-throughs.Regarding the global development and progress of quantum computing,the coher-ence time of superconducting qubits was merely 2ns in 1999,extending to 100μs by 2012,which laid the foundation for practical applications;In 2016,the world's first cloud-accessible 5-qubit processor was launched abroad,followed in 2019 by the first commercial quantum computer.That same year,a 53-qubit processor was claimed to have achieved"quantum su-premacy";however,this conclusion pertained to a specific abstract mathematical problem and lacked universal practical value.Chinese researchers have narrowed the computational power gap with supercomputers through new algorithms.However,the development of quantum computing in China has been hampered by foreign technology sanctions,with critical compo-nents such as dilution refrigerators once subject to embargo,but independent research and de-velopment has been achieved with commercialized exports now possible.A domestic quantum computing company released its third-generation superconducting quantum computer in early 2024,integrating 72 qubits(with over 100 including auxiliary qubits).With a domestic pro-duction rate of approximately 80%,the system has,following the opening of cloud access,reached users in 143 countries worldwide,with around 30 million registered users and over 520,000 computational tasks completed.In this report,Academician Guo divides the develop-ment of quantum computing into three stages:the prototype development stage,the quantum supremacy special-purpose machine stage,and the quantum-supercomputing fusion stage.The world has now entered a critical phase in the research and development of logical qubits,and China has achieved coherent control of over 500 physical qubits.In the future,the core appli-cations of quantum computing will focus on two major directions:firstly,cracking crypto-graphic systems that are difficult for classical computers to break;secondly,empowering AI to resolve current bottlenecks in AI computing power and high energy consumption issues,thereby driving the evolution from classical AI to quantum AI.The deep integration of quan-tum computing and AI will become the core driving force behind a new round of technological revolution and industrial transformation.
This paper proposes an instructional framework for physics teaching that takes the"Four Beauties"(technical,scientific,artistic,and humanistic)as four defining dimensions of classroom design and the"Three Openings"as progressive levels of student cognition.The framework provides practical pathways for fostering key competencies in physics,including the"Four Degrees and Eight Actions"model of teacher-student behavior,the ETA physics cognitive model,the"Three Laws of Teaching,"and a set of instructional design guidelines.With AI support,this framework enables the integrated generation of multiple versions of physics instructional designs across educational stages,from junior high school to university.It therefore offers a practical,scalable,and easily adaptable approach to competency-oriented physics teaching.
Youngu2019s modulus is a fundamental physical quantity that characterizes the elastic properties of materials and is of great importance in physics teaching and engineering applications. In this study, an adjustable bending-beam device for measuring Youngu2019s modulus was designed and fabricated based on 3D printing technology. The device has a modular structure, with adjustable support span, specimen interfaces, and loading configurations, allowing it to accommodate specimens with different cross-sectional shapes. To ensure measurement reliability, a complete measurement procedure and an uncertainty evaluation model were established. Measurements of an aluminum alloy beam yielded a Youngu2019s modulus of 70.12(57)GPa, with a deviation of less than 1% from the reference value. Measurements of a non-standard material, spaghetti, gave a value of 4.540(50)GPa, further demonstrating the applicability of the device in open-ended experiments. In addition, students can use 3D printing to independently design beams with different cross-sectional shapes and investigate the influence of cross-sectional geometry on bending stiffness. In this way, the experiment can be extended from simple parameter measurement to an inquiry-based task involving design and analysis. This work provides a low-cost and flexible solution for university physics experiments and helps bridge physical principles with engineering practice.
To address the teaching challenges in solid-state physics,such as the abstraction of core concepts and the disconnect between theoretical instruction and frontier research,this pa-per presents an inquiry-based teaching case centered on the band-structure study of twisted bi-layer MoS2.By introducing the frontier topic of twistronics into the classroom,the case guides students through the complete research process,including moiré superlattice construc-tion,structural optimization,and electron band-structure calculation and analysis.With the aid of the first-principles calculation software CASTEP and the crystal visualization software VES-TA,students construct a 21.79° twisted bilayer MoS2 model,optimize its atomic geometry,and ana-lyze its electronic band structure.This research-driven and computationally empowered teaching model helps students understand key concepts such as crystal symmetry and band theory,while also improving their abilities in computational simulation,data analysis,and complex problem solving.By integrating knowledge instruction,ability development,and exposure to frontier research,this case provides a practical paradigm for reforming foundational science and engineering courses.
