So aliens have arrived in the solar system.
- They have faster-than-light travel technology and the ability to handwave away the supposed causality violations that such an invention causes
- They're peaceful, and currently reside in orbit around Earth's moon
- They're from an isolated, antimatter galaxy, which means that they can't come to Earth, nor touch anything we manufacture. Conversely, nothing created on Earth can board their ships without risk
- The only thing stopping their ships from colliding with interstellar particles and exploding violently is a very strong electromagnetic field (see related ideas here)
Both parties want to converse up close but they cannot come in contact with each other. The location of these interactions does not matter. Neither party can change the charges of their own particles, nor can they manufacture technology with the opposite charge safely.
What are efficient ways for these two groups to communicate?
And if possible, what can allow close interaction (same room) to further scientific partnership between humans and this species without the risk of deadly particle collision?