diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json
index 16f58f2..ee1c149 100644
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@@ -216,6 +216,8 @@
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@@ -232,8 +234,6 @@
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diff --git a/SS2026/Quantum Computing/4. Observing and measuring/Observing probabilistic and measuring quantum systems.md b/SS2026/Quantum Computing/4. Observing and measuring/Observing probabilistic and measuring quantum systems.md
index 1a938d8..754c311 100644
--- a/SS2026/Quantum Computing/4. Observing and measuring/Observing probabilistic and measuring quantum systems.md	
+++ b/SS2026/Quantum Computing/4. Observing and measuring/Observing probabilistic and measuring quantum systems.md	
@@ -21,3 +21,21 @@ Measuring a quantum state CHANGES THE SYSTEM!!!
 
 ![[Pasted image 20260729094710.png]]
 ![[Pasted image 20260729094718.png]]
+
+
+## Elitzur-Vaidman bomb tester
+
+Given a box we want to determine whether it contains a bomb.
+To test, a photon can be send through the box.
+- if the bomb detects a photon it explodes!
+- if no bomb is present nothing happens
+
+![[Pasted image 20260729100407.png]]
+
+#### Beam Splitter
+
+![[Pasted image 20260729100435.png]]
+
+A beam splitter is a semi transparent mirror.
+Photons entering from up can come out on the up or down path - analog for down
+Quantum mechanically it could come in a superposition between up and down
\ No newline at end of file