📌 Formatting & Writing Guide Forum Posting Guidelines

imalightbulb · March 16, 2026, 9:43am

Welcome to Eigenspace, the official forum of the XMUM Physics Student Council. Before you dive in, take five minutes to read this guide. Good formatting makes your posts easier to read, easier to search, and much more likely to get useful replies.

1. The Basics — Markdown

Discourse uses Markdown for formatting.

Text Styling

**bold text**
*italic text*
~~strikethrough~~
`inline code`

Renders as: bold, italic, ~~strikethrough~~, inline code

Headings

# Heading 1
## Heading 2
### Heading 3

Use headings to organise long posts — especially useful for problem write-ups and paper discussions.

Lists

Unordered:

- First point
- Second point
  - Nested point

Ordered:

1. Derive the Hamiltonian
2. Apply boundary conditions
3. Profit

Blockquotes

Use > to quote a passage from a paper, textbook, or another post:

> "Anyone who is not shocked by quantum theory has not understood it."
> — Niels Bohr

“Anyone who is not shocked by quantum theory has not understood it.”
— Niels Bohr

Horizontal Rules

Use --- on its own line to separate sections cleanly.

2. Writing Mathematics

This is the most important section for a physics forum. Eigenspace supports KaTeX, a fast LaTeX math-rendering engine. Write standard LaTeX math syntax and it renders beautifully in your browser.

Inline Math — $ ... $

Wrap your expression in single dollar signs for inline math — math that sits within a sentence.

Syntax:

The energy eigenvalue equation is $\hat{H}|\psi\rangle = E|\psi\rangle$,
where $\hat{H}$ is the Hamiltonian operator.

Renders as:
The energy eigenvalue equation is \hat{H}|\psi\rangle = E|\psi\rangle, where \hat{H} is the Hamiltonian operator.

Use inline math for variables, short expressions, and notation within prose. Keep it readable — don’t cram a full derivation into one inline block.

Display Math — `$$ ... $$`

Wrap your expression in double dollar signs for display math — math rendered on its own centred line. Use this for important equations, results, and anything you want to stand out.

Syntax:

$$
\mathcal{L} = \bar{\psi}(i\gamma^\mu \partial_\mu - m)\psi
- \frac{1}{4}F_{\mu\nu}F^{\mu\nu}
$$

Renders as:

\mathcal{L} = \bar{\psi}(i\gamma^\mu \partial_\mu - m)\psi - \frac{1}{4}F_{\mu\nu}F^{\mu\nu}

Multi-line Equations — `aligned`

Use the aligned environment inside $$ ... $$ for derivations and systems of equations. Align your equals signs with &= and separate lines with \\.

Syntax:

$$
\begin{aligned}
\nabla \cdot \mathbf{E} &= \frac{\rho}{\varepsilon_0} \\
\nabla \cdot \mathbf{B} &= 0 \\
\nabla \times \mathbf{E} &= -\frac{\partial \mathbf{B}}{\partial t} \\
\nabla \times \mathbf{B} &= \mu_0 \mathbf{J}
  + \mu_0\varepsilon_0 \frac{\partial \mathbf{E}}{\partial t}
\end{aligned}
$$

Renders as:

\begin{aligned} \nabla \cdot \mathbf{E} &= \frac{\rho}{\varepsilon_0} \\ \nabla \cdot \mathbf{B} &= 0 \\ \nabla \times \mathbf{E} &= -\frac{\partial \mathbf{B}}{\partial t} \\ \nabla \times \mathbf{B} &= \mu_0 \mathbf{J} + \mu_0\varepsilon_0 \frac{\partial \mathbf{E}}{\partial t} \end{aligned}

Matrices

Syntax:

$$
\rho = \begin{pmatrix}
\rho_{00} & \rho_{01} \\
\rho_{10} & \rho_{11}
\end{pmatrix}
$$

Renders as:

\rho = \begin{pmatrix} \rho_{00} & \rho_{01} \\ \rho_{10} & \rho_{11} \end{pmatrix}

Use pmatrix for round brackets, bmatrix for square brackets, vmatrix for determinant bars.

Quick KaTeX Reference

What you want	Syntax
Fraction	`\frac{a}{b}`
Square root	`\sqrt{x}` or `\sqrt[n]{x}`
Subscript / Superscript	`x_i`, `x^2`, `x_i^2`
Greek letters	`\alpha \beta \gamma \hbar \psi \Psi`
Bra-ket notation	`\langle \psi \vert`, `\vert \phi \rangle`, `\langle \psi \vert \phi \rangle`
Sum / Integral	`\sum_{i=0}^{n}`, `\int_{-\infty}^{\infty}`
Partial derivative	`\frac{\partial f}{\partial x}`
Operators / hats	`\hat{H}`, `\nabla`, `\otimes`, `\oplus`
Bold vectors	`\mathbf{v}`
Calligraphic	`\mathcal{H}`, `\mathcal{L}`
Text inside math	`\text{for all } x`
Cases / piecewise	`\begin{cases} ... \end{cases}`
Commutator	`[A, B]` or `\left[A, B\right]`
Tensor product	`A \otimes B`
Expectation value	`\langle \hat{A} \rangle`
Trace	`\text{Tr}(\rho)`

Common mistakes:

Don’t leave a space between $ and the first character: $ \psi$ may fail; $\psi$ is correct.

Don’t use $$ ... $$ inline within a sentence — it will break the line. Use $ ... $ there.

If a backslash command isn’t rendering, check that KaTeX supports it (not all LaTeX packages are available).

3. Code Blocks

For sharing code — Python, Julia, Mathematica, LaTeX source, shell scripts — use triple backticks with the language name:

```python
import numpy as np

def bloch_vector(rho):
    sx = np.array([[0,1],[1,0]])
    sy = np.array([[0,-1j],[1j,0]])
    sz = np.array([[1,0],[0,-1]])
    return [np.trace(rho @ s).real for s in [sx, sy, sz]]
```

Supported language tags include: python, julia, mathematica, latex, bash, c, cpp, javascript, and more. If unsure, omit the tag — you’ll still get monospace formatting.

4. Links and Images

Links:

[Eigenspace Forum](https://forum.physicsxmum.my)
[arXiv: Ekert 1991](https://arxiv.org/abs/quant-ph/0101084)

Images:
Paste or drag-and-drop an image directly into the editor — Discourse handles the upload automatically. This is great for:

Photos of hand-written derivations
Screenshots of Mathematica or Python output
Diagrams drawn by hand or digitally

Always add a sentence of context below the image. A standalone picture with no explanation is hard for others to engage with.

5. Collapsible Sections

Use this for long derivations, hints to problems, or solutions you don’t want to spoil immediately. It keeps posts clean while making full content accessible.

Syntax:

[details="Click to expand: Full derivation"]

Starting from the Schrödinger equation...

$$
i\hbar \frac{\partial}{\partial t}|\psi(t)\rangle = \hat{H}|\psi(t)\rangle
$$

...your full derivation here.

[/details]

Renders as a collapsible block with the label as the toggle.

This is especially useful in the Problem Sets and Journal Club categories, where you may want to post a solution without spoiling it for everyone at once.

6. Tables

(Or click the + icon in the editor and add tables generates such a table easily)

| Symbol    | Meaning                   | SI Unit   |
|-----------|---------------------------|-----------|
| $E$       | Energy                    | J         |
| $p$       | Momentum                  | kg·m/s    |
| $\hbar$   | Reduced Planck constant   | J·s       |
| $S$       | Entropy                   | J/K       |

Renders as a clean, aligned table. Use tables for comparisons, symbol glossaries, and summaries of results.

7. Good Posting Habits

Choose the right category.
Browse the category list before posting. A question about a QM homework problem belongs in a different place than a paper discussion or an announcement. Miscategorised posts will be moved by moderators.

Write a descriptive title.
“Help with integral” is hard to find and easy to ignore. “Evaluating a Gaussian integral with complex argument in the path integral formalism” tells people exactly what they’re walking into — and shows up in searches six months later.

Show your work.
When asking for help on a problem, include what you’ve tried. Even a wrong approach tells others where you’re stuck, and prevents them from writing an answer that re-explains what you already know.

Cite your sources.
If you’re discussing a result or referring to a paper, link the arXiv page or DOI. Preferred format:

[Ekert, 1991 — Quantum cryptography based on Bell's theorem](https://arxiv.org/abs/quant-ph/0101084)

Use the preview pane.
The editor has a live preview on the right side. Always check that your KaTeX renders before posting — especially for long derivations. A broken equation is harder to follow than the LaTeX source.

Don’t double-post.
If you want to add something to your own post and nobody has replied yet, use the edit button (pencil icon) rather than posting again below. The edit history is preserved, so nothing is lost.

Keep notation consistent.
If your post introduces a symbol, define it. Readers shouldn’t have to guess whether \rho is a density matrix, a charge density, or a position vector in your context.

8. Reactions and Engagement

Like a post to show appreciation — especially for a clear explanation or a helpful answer. Likes help surface good content.
Reply to specific posts using the Reply button on that post (not the bottom bar) so threads stay properly nested and readable.
Flag anything that seems off-topic, spam, or inappropriate. Moderators will handle it.
Link between posts by copying the post’s share URL. This is useful in journal club threads when referring back to an earlier discussion.

This guide was written by the XMUM Physics Student Council. If anything is unclear or you’d like a section added, reply below or contact the council directly.

Last updated: March 2026

imalightbulb · March 17, 2026, 8:11am

Welcome to Eigenspace, the official forum of the Physics Student Association at Xiamen University Malaysia (XMUM). Before you start browsing, please take five minutes to read this guide. Good formatting makes your posts easier to read, searchable, and significantly increases the chances of getting helpful responses.

1. Basic Formatting — Markdown

The Discourse forum uses Markdown for formatting.

Text Styles
**Bold text**
*Italic text*
~~Strikethrough~~
`Inline code`
Rendered result: Bold text, Italic text, ~~Strikethrough~~, Inline code

Headings

# Heading 1
## Heading 2
### Heading 3

Use headings to organize long posts—this is especially useful for problem solutions and paper discussions.

Lists
Unordered list:

- First point
- Second point
  - Nested point

Ordered list:

1. Derive Hamiltonian
2. Apply boundary conditions
3. Obtain result

Blockquotes
Use > to quote paragraphs from papers, textbooks, or other posts:

“Anyone who is not shocked by quantum theory has not understood it.”
— Niels Bohr

Horizontal Rules
Use --- on a separate line to clearly separate sections.

2. Writing Mathematical Formulas

This is the most important part of the physics forum. Eigenspace supports KaTeX, a fast LaTeX math rendering engine. Simply write standard LaTeX math syntax, and it will render perfectly in your browser.

Inline Formulas — $ ... $
Wrap your expression in single dollar signs to indicate inline formulas—mathematical expressions embedded within sentences.
Syntax:

The energy eigenvalue equation is $\hat{H}|\psi\rangle = E|\psi\rangle$,
where $\hat{H}$ is the Hamiltonian operator.

Rendered result:
The energy eigenvalue equation is \hat{H}|\psi\rangle = E|\psi\rangle, where \hat{H} is the Hamiltonian operator.

Use inline formulas for variables, short expressions, and symbols within text descriptions. Keep them readable—don’t cram entire derivations into a single inline block.

Display Formulas — $$ ... $$
Wrap your expression in double dollar signs to indicate display math—the formula will be centered on its own line. Use this for important equations, results, and any content you want to highlight.
Syntax:

$$
\mathcal{L} = \bar{\psi}(i\gamma^\mu \partial_\mu - m)\psi
- \frac{1}{4}F_{\mu\nu}F^{\mu\nu}
$$

Rendered result:

\mathcal{L} = \bar{\psi}(i\gamma^\mu \partial_\mu - m)\psi - \frac{1}{4}F_{\mu\nu}F^{\mu\nu}

Multi-line Equations — aligned
Use the aligned environment inside $$ ... $$ to write derivations and equation systems. Use &= to align equal signs and \\ to break lines.
Syntax:

$$
\begin{aligned}
\nabla \cdot \mathbf{E} &= \frac{\rho}{\varepsilon_0} \\
\nabla \cdot \mathbf{B} &= 0 \\
\nabla \times \mathbf{E} &= -\frac{\partial \mathbf{B}}{\partial t} \\
\nabla \times \mathbf{B} &= \mu_0 \mathbf{J}
  + \mu_0\varepsilon_0 \frac{\partial \mathbf{E}}{\partial t}
\end{aligned}
$$

Rendered result:

\begin{aligned} \nabla \cdot \mathbf{E} &= \frac{\rho}{\varepsilon_0} \\ \nabla \cdot \mathbf{B} &= 0 \\ \nabla \times \mathbf{E} &= -\frac{\partial \mathbf{B}}{\partial t} \\ \nabla \times \mathbf{B} &= \mu_0 \mathbf{J} + \mu_0\varepsilon_0 \frac{\partial \mathbf{E}}{\partial t} \end{aligned}

Matrices
Syntax:

$$
\rho = \begin{pmatrix}
\rho_{00} & \rho_{01} \\
\rho_{10} & \rho_{11}
\end{pmatrix}
$$

Rendered result:

\rho = \begin{pmatrix} \rho_{00} & \rho_{01} \\ \rho_{10} & \rho_{11} \end{pmatrix}

Use pmatrix for parentheses, bmatrix for square brackets, vmatrix for determinant bars.

Quick KaTeX Reference Table

Effect	Syntax
Fractions	`\frac{a}{b}`
Square roots	`\sqrt{x}` or `\sqrt[n]{x}`
Subscripts/superscripts	`x_i`, `x^2`, `x_i^2`
Greek letters	`\alpha \beta \gamma \hbar \psi \Psi`
Bra-ket notation	`\langle \psi \vert`, `\vert \phi \rangle`, `\langle \psi \vert \phi \rangle`
Summation/integral	`\sum_{i=0}^{n}`, `\int_{-\infty}^{\infty}`
Partial derivatives	`\frac{\partial f}{\partial x}`
Operators/hats	`\hat{H}`, `\nabla`, `\otimes`, `\oplus`
Bold vectors	`\mathbf{v}`
Calligraphic font	`\mathcal{H}`, `\mathcal{L}`
Text inside math	`\text{for all } x`
Piecewise functions/conditions	`\begin{cases} ... \end{cases}`
Commutators	`[A, B]` or `\left[A, B\right]`
Tensor product	`A \otimes B`
Expectation values	`\langle \hat{A} \rangle`
Trace	`\text{Tr}(\rho)`

Common Errors:

Do not leave spaces between $ and the first character: $ \psi$ may fail to render; $\psi$ is correct.
Do not use $$ ... $$ inline within sentences—it breaks the line. Use $ instead.
If a backslash command doesn’t render, check if KaTeX supports it (not all LaTeX packages are available).

3. Code Blocks

To share code—Python, Julia, Mathematica, LaTeX source, or shell scripts—use triple backticks with the language name:

import numpy as np

def bloch_vector(rho):
    sx = np.array([[0,1],[1,0]])
    sy = np.array([[0,-1j],[1j,0]])
    sz = np.array([[1,0],[0,-1]])
    return [np.trace(rho @ s).real for s in [sx, sy, sz]]

Supported language tags include: python, julia, mathematica, latex, bash, c, cpp, javascript, etc. If unsure, omit the tag—you’ll still get monospaced code formatting.

4. Links and Images

Links:

[Eigenspace Forum](https://forum.physicsxmum.my)
[arXiv: Ekert 1991](https://arxiv.org/abs/quant-ph/0101084)

Images:
Paste or drag images directly into the editor—Discourse handles the upload automatically. This is great for:

Photos of handwritten derivations
Screenshots of Mathematica or Python output
Hand-drawn or digitally created diagrams

Please add a one-sentence caption below images. A standalone image without explanation is difficult for others to engage with.

5. Collapsible Sections

For long derivations, problem hints, or answers you don’t want to spoil immediately, use this feature. It keeps posts tidy while ensuring full content is available.

Syntax:

[details="Click to expand: Full derivation"]

Starting from the Schrödinger equation...

$$
i\hbar \frac{\partial}{\partial t}|\psi(t)\rangle = \hat{H}|\psi(t)\rangle
$$

...write your complete derivation here.

[/details]

The rendered result will be a collapsible section with the label text as the toggle button.

This is particularly useful in the “Problem Sets” and “Journal Club” categories where you can post answers without spoiling everything for everyone at once.

6. Tables

(Or simply click the + icon in the editor and select “Add Table” for an easy generation)

| Symbol      | Meaning                     | SI Unit |
|-------------|-----------------------------|---------|
| $E$         | Energy                      | J       |
| $p$         | Momentum                    | kg·m/s  |
| $\hbar$     | Reduced Planck constant     | J·s     |
| $S$         | Entropy                     | J/K     |

Renders as a neatly aligned table. Use tables for comparisons, creating symbol glossaries, or summarizing results.

7. Good Posting Habits

Choose the right category. Browse the category list before posting. A question about quantum mechanics homework belongs in a different section than a paper discussion or announcement. Posts in the wrong category will be moved by moderators.
Write descriptive titles. “Help with integral problem” is hard to find and easy to ignore. “Calculating Gaussian integrals with complex parameters in path integral formalism” clearly tells people what’s being discussed—and will appear in search results six months later.
Show your thought process. When seeking help with a problem, include what you’ve already tried. Even a wrong direction tells people where you’re stuck and prevents them from writing explanations you already know.
Cite your sources. If you’re discussing a result or quoting a paper, include arXiv links or DOIs. Recommended format:
[Ekert, 1991 — Quantum cryptography based on Bell's theorem](https://arxiv.org/abs/quant-ph/0101084)
Use the preview panel. There’s a live preview on the right side of the editor. Always check your KaTeX renders correctly before posting—especially for long derivations. A broken formula is more frustrating than raw LaTeX source.
Don’t double post. If you want to add something to your post and no one has replied yet, use the edit button (pencil icon) instead of posting below. Edit history is saved, so nothing is lost.
Be consistent with symbols. If your post introduces a symbol, define it. Readers shouldn’t have to guess whether \rho is a density matrix, charge density, or position vector.

8. Interaction and Engagement

Like posts to show appreciation—especially for clear explanations or helpful answers. Likes help good content get visibility.
Use the Reply button on specific posts (not the global reply at the bottom) so discussion threads maintain proper nesting and readability.
Flag any off-topic, spam, or inappropriate content. Moderators will handle it appropriately.
Cross-reference posts by copying the share link from posts. This is very useful in Journal Club discussion threads when referring back to earlier discussions.

This guide was written by the XMUM Physics Student Association. If anything is unclear or you’d like to add new sections, please reply below or contact the student association directly.
Last updated: March 2026

📌 Formatting & Writing Guide Forum Posting Guidelines

1. The Basics — Markdown

Text Styling

Headings

Lists

Blockquotes

Horizontal Rules

2. Writing Mathematics

Inline Math — $ ... $

Display Math — $$ ... $$

Multi-line Equations — aligned

Matrices

Quick KaTeX Reference

3. Code Blocks

4. Links and Images

5. Collapsible Sections

6. Tables

7. Good Posting Habits

8. Reactions and Engagement

1. Basic Formatting — Markdown

2. Writing Mathematical Formulas

3. Code Blocks

4. Links and Images

5. Collapsible Sections

6. Tables

7. Good Posting Habits

8. Interaction and Engagement

Display Math — `$$ ... $$`

Multi-line Equations — `aligned`