Abstract A laboratory experiment and related computational activities for advanced undergraduate or introductory graduate students on quantum entanglement are developed and described. Students characterize the quality of entanglement of a system, use code to predict the best experimental parameters for the system, and then perform a modified Bell measurement. The results can show non-classical behavior for any (non-zero) level of entanglement. Demonstration of the experiment on an IBM quantum computer is also shown, including the additional effects of decoherence on such a system. While a potentially interesting experiment for any program, it can open new avenues of education particularly for smaller colleges and universities on a more limited budget.
Abstract A laboratory experiment and related computational activities for advanced undergraduate or introductory graduate students on quantum entanglement are developed and described. Students characterize the quality of entanglement of a system, use code to predict the best experimental parameters for the system, and then perform a modified Bell measurement. The results can show non-classical behavior for any (non-zero) level of entanglement. Demonstration of the experiment on an IBM quantum computer is also shown, including the additional effects of decoherence on such a system. While a potentially interesting experiment for any program, it can open new avenues of education particularly for smaller colleges and universities on a more limited budget.
Abstract We present educational material about Bell inequalities in the context of quantum computing. In particular, we provide software tools to simulate their violation, together with a guide for classroom discussion. The material is organized in three modules of increasing difficulty, and the relative implementation has been written in Qibo, an open-source software suite to simulate quantum circuits with the ability to interface with quantum hardware. The topic of inequalities allows us to not only introduce undergraduate or graduate students to crucial theoretical issues in quantum mechanics, such as entanglement, correlations, hidden variables and non-locality, but also to practically put hands on tools to implement a real simulation, where statistical aspects and noise coming from current quantum chips also come into play.
Abstract This laboratory work presents a practical introduction to the preparation and analysis of entangled quantum states (Bell pairs) using the Qiskit framework. The material is based on educational resources developed by the International Quantum Center at CERN (Switzerland) and is designed to provide hands-on experience with multi-qubit quantum circuits and entanglement generation. In Laboratory Work No. 3, participants construct and simulate a quantum circuit that prepares an entangled two-qubit state. As a representative example of multi-qubit operations in Qiskit, the circuit generates a Bell state by applying a Hadamard (H) gate to the first qubit q[0]q[0]q[0], followed by a controlled-NOT (CNOT) gate with q[0]q[0]q[0] as the control qubit and q[1]q[1]q[1] as the target qubit. This sequence creates a maximally entangled state, demonstrating the fundamental non-classical correlations characteristic of quantum systems. The laboratory exercise includes measurement operations applied to both qubits, illustrating how entanglement manifests in correlated classical outcomes. When the measurement operator is applied to the first qubit q[0]q[0]q[0], the corresponding classical bit records a definite value, and subsequent measurement of the second qubit q[1]q[1]q[1] yields a correlated result consistent with the structure of the Bell state. The probabilistic yet correlated outcomes provide direct evidence of quantum entanglement. The guide emphasizes the conceptual understanding of entanglement, circuit implementation in Qiskit, and the hybrid quantum-classical workflow underlying quantum computation. By bridging theoretical quantum mechanics with executable quantum circuits, this laboratory work enables students and researchers to experimentally explore one of the central phenomena of quantum information science using cloud-based quantum computing resources.
In 1964, J. Bell introduced an inequality that stated a mathematical bound for any physical system that holds both locality and realism; if we violate this inequality, it is clear that we have to reconsider the previous statement. In our work, we report an experimental activity with photons suitable for undergraduate students that makes them question these naïve ideas of nature’s behavior. With a pre-aligned setup, our students tested and violated Bell’s inequality in a two-hour laboratory session, using two distant photons entangled in polarization. In addition, complementing an educational approach to this phenomenon, the usually called S function, that quantifies correlations, was mapped using different detection angles in one of the two locations. In particular, a more complete picture of the S function, allow us to identify the initial state of light. We show in this work that it is possible for undergraduate students to question some of our common sense ideas of nature using experiments with photons.
Quantum entanglement has gained significant attention in recent years owing to its diverse application in quantum informatics. Its nonlocal nature makes it a crucial resource in quantum information, especially in quantum communication and networking. Entanglement plays a vital role in advancing quantum computation and technology.This study discusses the creation of entangled quantum states using photon pairs and the measurement of entanglement, utilizing the IBM Q Experience the first industrial initiative to develop universal quantum computers and provide widespread access to these technologies through cloud platforms. The introduction of the Qiskit tool has enabled researchers, educators, developers, and enthusiasts to write code and conduct experiments on quantum machines. In this study, we implemented and tested circuits on the IBM Q quantum computing platform using Qiskit to execute quantum computing programs such as the Bell Inequality, CHSH Inequality, and Five-Qubit GHZ States, with two successful programming presented, these tools, along with the associated Jupyter Notebook pages, serve as additional resources for users of the IBM Q Experience. We present the results which will help evaluate these prototypes’ performance. Where quantum computers are designed to process information units that go beyond mere abstract mathematical entities, as suggested by Shannon’s theory; instead, they represent real physical objects defined by one of the two fundamental physical theories—quantum mechanics.
Entanglement, a phenomenon that has puzzled scientists since its discovery, has been extensively studied by many researchers through both theoretical and experimental aspect of both quantum information processing (QIP) and quantum mechanics (QM). But how can entanglement be most effectively taught to computer science students compared to applied physics students?. in this educational pursuit, we propose using Yao.jl, a quantum computing framework written in Julia for teaching entanglement to graduate computer science students attending a quantum computing class at Johns Hopkins University. David Mermin's just enough QM for them to understand and develop algorithms in quantum computation [Mer98, Mer03] idea aligns with the purpose of this work. Additionally, the authors of the study Improving students understanding of QM via the Stern-Gerlach experiment (SGE) argue that this experiment should be a key part of any QM education. Here, we explore the concept of entanglement and it's quantification in various quantum information processing experiments, including one inequality-free form of Bell's theorem: (1) Superposition via the Hadamard, (2) Bell-state generation and (3) GHZ state generation. The utilisation of circuit diagrams and code fragmentsis a central theme in this work's philosophy.
With quantum computing’s potential to be exponentially more powerful than classical computing, due to superposition and entanglement, several companies including IBM have started to develop quantum computers. Since 2016, IBM has developed publicly accessible cloud-based quantum computers. While the development of quantum computing can revolutionize decryption, optimization, and the simulation of quantum systems, quantum computers must maintain a high level of accuracy as they are scaled up. This paper introduces the fundamental gates used on IBM’s quantum computers and provides visualizations of each gate. A thought experiment involving two quantum entangled particles is used to explain the Einstein-Podolsky-Rosen Paradox, and two potential explanations are introduced: violation of locality and the Hidden Variable Theory. Experimental results are reported for the quality of entanglement created on IBM’s publicly accessible 5-qubit quantum computers by creating entanglement between 2 qubits and then measuring both qubits along a set combination of axes, and demonstrating the violation of the Bell-CHSH Inequality. Six out of seven 5-qubit quantum computers violated the Bell-CHSH Inequality, thus demonstrating strong quantum entanglement between 2 qubits, a standard crucial for scaling up quantum computers to harness their exponentially scaling power.