World Quantum Day, observed annually on 14 April, celebrates the importance of quantum science and technology and raises public awareness of its role in shaping the future. The date 14 April references 4.14, the rounded first digits of Planck’s constant, a fundamental constant at the heart of quantum physics. World Quantum Day highlights how quantum research continues to expand our understanding of the universe while driving innovation across computing, communication, sensing, materials, and other emerging technologies.

In recognition of World Quantum Day, MDPI reaffirms its commitment to advancing cutting-edge and interdisciplinary research. Through open access publishing, we support the dissemination of discoveries in quantum science, applied physics, engineering, and related fields—ensuring knowledge is accessible and empowering researchers to contribute to the next generation of scientific and technological breakthroughs.

“Quantum-Spacetime Perspective on the KM3-230213A Neutrino”
by Giovanni Amelino-Camelia, Giacomo D’Amico, Giuseppe Fabiano, Domenico Frattulillo, Giulia Gubitosi, Alessandro Moia and Giacomo Rosati
Time Space 2026, 2(1), 2; https://doi.org/10.3390/timespace2010002

“Dynamics of Information Quantifiers in the Damped Rabi Oscillator”
by Flavia Pennini and Angelo Plastino
Foundations 2026, 6(1), 5; https://doi.org/10.3390/foundations6010005

“Enhanced Quantum Dot Emission in Fibonacci Photonic Crystal Cavities Optimized for PECVD-Compatible Porous Silicon: A Computational Study”
by J. E. Mastache-Mastache, M. C. González, H. Martínez and B. Reyes-Ramírez
Plasma 2026, 9(1), 1; https://doi.org/10.3390/plasma9010001

“Generalized Miller Formulae for Quantum Anharmonic Oscillators”
by Maximilian T. Meyer and Arno Schindlmayr
Dynamics 2025, 5(3), 34; https://doi.org/10.3390/dynamics5030034

“Intertwined Orders and the Physics of High Temperature Superconductors”
by Eduardo Fradkin
Particles 2025, 8(3), 70; https://doi.org/10.3390/particles8030070

“Electro-Optical Modulation of the Nonlinear Optical Response in a GaAs/AlGaAs Symmetric Multiple Quantum Well System”
by Carlos Alberto Dagua-Conda, John Alexander Gil-Corrales, Rebeca Victoria Herrero-Hahn, Miguel Eduardo Mora-Ramos, Alvaro Luis Morales and Carlos Alberto Duque
Physics 2025, 7(2), 22; https://doi.org/10.3390/physics7020022

“Measurement-Induced Symmetry Restoration and Quantum Mpemba Effect”
by Giuseppe Di Giulio, Xhek Turkeshi and Sara Murciano
Entropy 2025, 27(4), 407; https://doi.org/10.3390/e27040407

“Statistics of Quantum Numbers for Non-Equivalent Fermions in Single-j Shells”
by Jean-Christophe Pain
Atoms 2025, 13(4), 25; https://doi.org/10.3390/atoms13040025

“Quantum-Ordering Ambiguities in Weak Chern—Simons 4D Gravity and Metastability of the Condensate-Induced Inflation”
by Panagiotis Dorlis, Nick E. Mavromatos and Sotirios-Neilos Vlachos.
Universe 2025, 11(1), 15; https://doi.org/10.3390/universe11010015

“A Comprehensive Review of Quantum Circuit Optimization: Current Trends and Future Directions”
by Krishnageetha Karuppasamy, Varun Puram, Stevens Johnson and Johnson P. Thomas
Quantum Rep. 2025, 7(1), 2; https://doi.org/10.3390/quantum7010002

“Magnetic Hopfions: A Review”
by Konstantin Guslienko
Magnetism 2024, 4(4), 383-399; https://doi.org/10.3390/magnetism4040025

“de Broglie, General Covariance and a Geometric Background to Quantum Mechanics”
by Basil Hiley and Glen Dennis
Symmetry 2024, 16(1), 67; https://doi.org/10.3390/sym16010067

“Quantum Optics: Communication, Sensing, Computing, and Simulation” Guest Editors: Dr. Peng Xu, Prof. Dr. Dong Wang, Dr. Wei Xiong Deadline for submissions: 20 June 2026	“Quantum Theory 100 Years Later: Advances on Foundations and Applications” Guest Editors: Prof. Dr. Iver H. Brevik, Prof. Dr. Roberto Passante and Prof. Dr. Akbar Salam Deadline for submissions: 30 June 2026
“Superconducting Spin Dynamics and Quantum Effects” Guest Editor: Dr. Yunyan Yao Deadline for submissions: 30 June 2026	“New Horizons in Antiferromagnetic Spintronics: Exotic Ground States and Device Prospects” Guest Editors: Dr. Pingfan Gu, Dr. Yuxuan Peng and Dr. Shiqi Yang Deadline for submissions: 31 July 2026
“Quantum Technologies in Cold Atomic Systems” Guest Editor: Dr. Andrea Richaud Deadline for submissions: 31 August 2026	“Photoacoustic Imaging and Sensing: New Developments and Horizons” Guest Editors: Dr. Mario Siciliani de Cumis, Dr. Stefano Dello Russo and Dr. Jacopo Pelini Deadline for submissions: 20 October 2026

“The 2nd Electronic Conference on Universe” Organizers: MDPI and Universe Volume Editor: Lorenzo Iorio Highlights “Quantum Gravitational Non-Singular Tunneling Wavefunction Proposal” by Meysam Motaharfar and Parampreet Singh “A Rotating Model of a Light Speed Expanding Hubble-Hawking Universe” by U. V. Satya Seshavatharam and S. Lakshminarayana Click here to read the full list of papers.