# Quantum Mechanics

The Schrödinger Equation

$$iħ\frac{∂}{∂t}Ψ({\bf r},t)=-\frac{ħ^2}{2m}∇^2Ψ({\bf r},t)$$

Using Hamiltonian,

$$iħ\frac{∂}{∂t}Ψ({\bf r},t)=\hat{H}Ψ({\bf r},t)$$

In this post, after deriving the Schrödinger Equation equation, we obtain the momentum operator.

In quantum mechanics, use bra vector  $<a|$ and ket vector $|a>$. What are the advantages of introducing them?

In quantum mechanics, we believe that every object has both particle and wave properties. If so, there should be rules for linking the properties of the particles and those of the waves.

De Broglie suggested the following equation, thinking that particles with masses such as protons and electrons can also be regarded as waves.

$$λ=\frac{h}{p}$$

$h$ is Planck’s constant, $p$ is the particle momentum. Then the particle has the same properties as wave of wavelength $λ$. This wavelength $λ$ is called the de Broglie wavelength.

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In this post, we’ll discuss what solving Schrödinger’s equation brings us by considering the physical meaning of the wave function.

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On 20th November 2017, NTT announced a system using domestic quantum computer for general people. Recently we often hear about quantum computers, but what is the difference between such computers and ordinary computers?

In this article, I will briefly touch on the difference between quantum computer and conventional computer, and a quantum dot used for quantum computer.