What are the potential performance differences between using single quotes and double quotes in PHP?

Using single quotes in PHP is generally faster than using double quotes because PHP does not have to search for variables within the string when using single quotes. If you do not need to include variables or special characters within the string, it is recommended to use single quotes for better performance.

// Single quotes example
$string = 'This is a string with single quotes';
```

```php
// Double quotes example
$string = "This is a string with double quotes";