The memory-simulating device in Assassin's Creed is called the Animus.
In the series, the Animus lets a user experience genetic memories inherited from ancestors. Modern characters enter or connect to the machine while the player explores historical periods through an ancestor's perspective. This device explains how a contemporary story can connect to many different historical settings.
The Animus is also a major narrative tool. Desmond Miles uses it to relive Altaïr's memories in the first game, and later characters use updated versions for research, training, entertainment, or corporate exploitation. The fictional technology therefore links the modern-day and historical plots.
Helix is a later entertainment and research platform associated with Abstergo, not the original generic name for the machine. Eagle Vision is a perception ability, while the Leap of Faith is an acrobatic descent. Neither is a memory-reading device.