Results 151 to 160 of about 17,306,746 (301)

Simple space-time symmetries in quantum field theory

open access: yes, 2004
In this thesis a program to study quantum field theories with simple space-time symmetries is introduced. These symmetries are given by simple Lie groups which are required to act on the Hilbert space of states by unitary positive energy representations (
Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)   +1 more
core   +1 more source

Achieving High ON State Current through Ferroelectric Polarization‐Dependent Interfacial Resistance Switching in Undoped Orthorhombic HfO2 Films

open access: yesAdvanced Functional Materials, EarlyView.
Ferroelectric tunnel junction devices based on epitaxial undoped ferroelectric HfO2 films demonstrate stable switching endurance of over 106 switching cycles, low write voltages of ±3 V, 16 measured resistance states, and neuromorphic capability.
Markus Hellenbrand   +13 more
wiley   +1 more source

Glissile Interphase Boundaries Enable Collective Phase Switching in Epitaxial Polar Oxides

open access: yesAdvanced Functional Materials, EarlyView.
A triple point is identified in the phase diagram of low‐symmetry epitaxial BiFeO3 thin film along with an extended regime of phase competition associated with a flattened energy landscape. The electromechanical response is shown to be governed by correlated interphase‐boundary motion, including scale‐free avalanche dynamics characteristic of systems ...
Mohammad Moein Seyfouri   +11 more
wiley   +1 more source

Gauge symmetries and Noether currents in optimal control [PDF]

open access: yes, 2003
We extend the second Noether theorem to optimal control problems which are invariant under symmetries depending upon k arbitrary functions of the independent variable and their derivatives up to some order m.
Torres, D.F.M.
core   +1 more source

Advances in Sustainable and Wearable Textile Based Soft Robotics

open access: yesAdvanced Functional Materials, EarlyView.
This Review examines advances in wearable textile‐based soft robotics, focusing on sustainable materials, integrated sensing, and scalable actuation. It discusses manufacturing and system integration across healthcare, assistive robotics, prosthetics, and human–machine interfaces, and highlights key challenges in circular design, including life‐cycle ...
Zahir Abbas   +6 more
wiley   +1 more source

Laws, Symmetry, and Symmetry Breaking; Invariance, Conservation Principles, and Objectivity [PDF]

open access: yes, 2002
Given its importance in modern physics, philosophers of science have paid surprisingly little attention to the subject of symmetries and invariances, and they have largely neglected the subtopic of symmetry breaking.
Earman, John
core  

Structure‐Guided Dynamical Mechanics in Bioinspired Double Twisted Laminated Thin Films

open access: yesAdvanced Functional Materials, EarlyView.
This work explores a dynamic mechanistic study of crack propagation and puncture testing via real‐time monitoring of crack initiation, propagation, and termination through nature‐inspired single and double twisted architectures fabricated from cellulose nanocrystals.
Justin Brackenridge   +4 more
wiley   +1 more source

Giant Magnetic Coercivity Driven by Spin‐Bag Ferromagnetism in Epitaxial Sr3YCo4O10+δ Films with Engineered 2D Oxygen Vacancy Ordering

open access: yesAdvanced Functional Materials, EarlyView.
A giant magnetic coercivity and a vertical shift of hysteresis loops are demonstrated in Sr3YCo4O10+δ epitaxial films. The hard magnetic behavior originates from ferromagnetic spin bags stabilized within a long‐range ordered oxygen‐vacancy structure.
Yanbin Chen   +12 more
wiley   +1 more source

Room‐Temperature Synthesis of Strongly Confined Lead Halide Perovskite Quantum Dots

open access: yesAdvanced Functional Materials, EarlyView.
CsPbX3${\rm CsPbX}_3$ lead halide perovskite quantum dots (QDs) are synthesized in a room‐temperature, five‐minute synthesis, yielding size‐controlled QDs with bright, tunable emission governed by reaction conditions and halide composition. A strongly binding ligand, OD‐PEA, ensures months‐long stability under ambient conditions and facilitates their ...
Anna Abfalterer   +13 more
wiley   +1 more source

Optical Signature of Moiré Superlattices Formed by Twisted SrTiO3 Membranes

open access: yesAdvanced Functional Materials, EarlyView.
We discover optical signatures from bonded interfaces in twisted SrTiO3 moiré superlattices, including low‐frequency Raman vibrational modes and strong second‐harmonic generation, consistent with strong interlayer coupling inferred from cross‐sectional electron microscopy and ab initio calculations. ABSTRACT Moiré superlattices formed at the interfaces
T. A. M. Ragib Shahriar   +13 more
wiley   +1 more source

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