Entanglement, Its Challenges and Its Applications

Michele Cini

Xiaoci Liu

This paper delves into the significance and impact of quantum entanglement across the fields of physics, information science, and philosophy. Utilizing a literature review approach, the paper first introduces the concept and historical background of quantum entanglement, emphasizing its challenge to the limitations of classical physics and its potential applications in quantum communication and quantum computing. This paper thoroughly explains the theoretical foundations of the Einstein-Podolsky-Rosen experiment and Bell's inequality, along with related experimental validations and key results. In particular, it elucidates how quantum entanglement reveals the nonlocality in quantum mechanics and the characteristics of nonlocal information transfer. The discussion then shifts to the challenge quantum entanglement poses to physical ontology, exploring the philosophical implications and the new perspectives it offers in information theory. Finally, this study concludes by summarizing the profound impact of quantum entanglement as one of the most challenging and inspiring research areas in contemporary physics on scientific theory and philosophical thought, as well as anticipating future research directions and potential applications.

Shengjun Wu

Shyam R. Sihare, V V Nath

Quantum cryptography is marches towards secure communication by using quantum protocols.Number of quantum protocols has been evolved based on an entanglement in three decades; similarly during this meanwhile non-entanglement based protocols have been evolved within the same period also.Among number of different protocols a torch bearer was BB84 protocol.Even though different quantum communication protocols exist, the BB84 protocol proved its application by initial experiments whereas most of the other protocols are theoretical which marches towards the practical application yet.But in quantum mechanics principle, cryptography based on an entanglement and superposition of entangled particle.Furthermore, challenges ahead are development and design high sensitive equipments for measurement of an entangled particle position at output end.Particle entanglements open a new door for computation worlds such as speedup, security.In this article, we discuss quantum protocols, their challenges, and applications based on above discussion.

Aditi Sen

Amit Behera, Alper Cakan, Vipul Goyal

A main application of quantum information in cryptography is copy-protection, where we encode a functionality (such as a decryption key or software) into a reusable quantum state so that it cannot be split into two adversaries (called freeloaders) that both remain useful. Previous works have only shown security for independently sampled challenges for the two adversaries. A competing natural security notion is identical-challenge security where the adversaries receive the same challenge. This notion has many real-life applications and connections to other fundamental primitives such as unclonable bits (i.e. unclonable encryption) and unclonable lockboxes (i.e. copy-protection of point functions). Despite its importance and numerous attempts, achieving identical-challenge security in the plain model has remained open. We first make progress on the definitional foundations of copy-protection by introducing natural copy-protection security definitions that imply the previous ones (including identical-challenge security) and better capture the security intuitions and real-life use cases; and we also characterize the relationship between the previous definitions. Then, we show how to achieve in the plain model our new stronger definitions for copy-protection of general classes of functionalities. In particular, we resolve the long-standing open questions of copy-protection of point functions, copy-protection of compute-and-compare programs, and identical-challenge secure copy-protection of decryption keys and all puncturable functionalities. Our technical core is a new decisional monogamy-of-entanglement result for coset states, which both allows us to achieve our new results, and also significantly simplifies and unifies unclonable cryptography proofs. We believe this will have further applications and may be of independent interest.