関連する実験動画

Updated: May 8, 2026

Preparing an Isotopically Pure 229Th Ion Beam for Studies of 229mTh
10:42

Preparing an Isotopically Pure 229Th Ion Beam for Studies of 229mTh

Published on: May 3, 2019

10(-18) の不安定性を有する原子時計

N Hinkley1, J A Sherman, N B Phillips

  • 1National Institute of Standards and Technology (NIST), Boulder, CO 80305, USA.

Science (New York, N.Y.)
|August 24, 2013
PubMed
まとめ

超冷たいイテルビウム原子を使用した2つの新しい原子時計は,前例のないタイムキーピングの不安定性を達成します. この画期的な発見は,ジオデシー,ナビゲーション,そして基礎物理学の研究におけるアプリケーションの精密タイミングを進歩させています.

さらに関連する動画

In Situ Measurement of Vacuum Window Birefringence using 25Mg+ Fluorescence07:03

In Situ Measurement of Vacuum Window Birefringence using 25Mg+ Fluorescence

Published on: June 13, 2020

Picometer-Precision Atomic Position Tracking through Electron Microscopy15:04

Picometer-Precision Atomic Position Tracking through Electron Microscopy

Published on: July 3, 2021

関連する概念動画

Nuclear Stability03:18

Nuclear Stability

Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10−15 meters, a nucleus is quite small compared to the radius of the entire atom, which is about 10−10 meters. Nuclei are extremely dense compared to bulk matter, averaging 1.8 × 1014 grams per cubic centimeter. If the earth’s density were equal to the average nuclear density, the earth’s radius would be only about 200 meters.
To hold positively charged protons together in the...
Atomic Nuclei: Larmor Precession Frequency01:11

Atomic Nuclei: Larmor Precession Frequency

The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession, and the angular frequency...
Atomic Nuclei: Types of Nuclear Relaxation01:28

Atomic Nuclei: Types of Nuclear Relaxation

Nuclear relaxation restores the equilibrium population imbalance and can occur via spin–lattice or spin–spin mechanisms, which are first-order exponential decay processes.
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers energy to a nearby...
Radioactive Decay and Radiometric Dating02:48

Radioactive Decay and Radiometric Dating

Radioactivity is a spontaneous disintegration of an unstable nuclide and is a random process, as all the nuclei in the sample do not decay simultaneously. The number of disintegrations per unit time is called the activity (A), which is directly proportional to the number of nuclei in the sample. The decay constant (λ) is an average probability of decay per nucleus in unit time.
Atomic Nuclei: Nuclear Magnetic Moment00:59

Atomic Nuclei: Nuclear Magnetic Moment

All atomic nuclei are positively charged. When they have a nonzero spin, they behave like rotating charges. As a consequence of their charge and spin, these nuclei generate a magnetic field (B). This, in turn, gives rise to a magnetic moment (μ), which is randomly oriented in the absence of an external magnetic field. When an external magnetic field (B0) is applied, the magnetic moment vectors can align with the field or against it in 2 + 1 orientations. A hydrogen nucleus, which is just a...
Atomic Mass01:52

Atomic Mass

Atoms — and the protons, neutrons, and electrons that compose them — are extremely small. For example, a carbon atom weighs less than 2 × 10−23 g. When describing the properties of tiny objects such as atoms, we use appropriately small units of measure, such as the atomic mass unit (amu). The amu was originally defined based on hydrogen, the lightest element, then later in terms of oxygen. Since 1961, it has been defined with regard to the most abundant isotope of carbon, atoms of which are...