Quantum entanglement is one of the most mysterious and profound phenomena in quantum physics — a phenomenon that Einstein once called “spooky action at a distance.”
But what is it, exactly?
🔹 Basic Definition
Quantum entanglement is a physical phenomenon in which two or more particles become linked, such that the state of one immediately affects the state of the other(s), no matter how far apart they are in space.
In other words:
Once entangled, particles no longer have independent states.
They exist in a shared, non-separable quantum state.
🔹 A Simple Example
Imagine two electrons, A and B, created in such a way that:
- If A is measured to have spin up,
- then B will always be spin down — and vice versa.
Now, you take electron A to the Andes, and electron B to the Himalayas.
You measure A’s spin — and it’s “up.”
Instantly, without any signal passing between them, B’s spin is “down.”
Even if they are light-years apart, their measurements are still perfectly correlated.
This defies classical intuition — where things should only affect each other locally and through causal interaction.
🔹 What Makes Entanglement So Radical?
1.
Nonlocality
- Entangled particles seem to influence each other instantaneously, defying the speed of light.
- Yet this doesn’t allow faster-than-light communication — it only shows that reality is not locally deterministic.
2.
Loss of Individuality
- After entanglement, particles don’t have independent identities.
- You can’t describe one without simultaneously describing the other.
- In a deep sense, they form a single system, even when spatially separated.
3.
Measurement Creates Reality
- Before measurement, the entangled system is in a superposition — neither spin up nor down.
- Measurement of one particle collapses the wave function of both, in perfect correlation.
- Reality is co-constructed in the act of measurement.
🔹 Barad’s Reading (In
Meeting the Universe Halfway
)
Karen Barad draws on entanglement to dismantle the subject-object divide:
- Just as particles do not exist independently before measurement,
- So too, knowers and known, observer and observed, do not pre-exist their intra-action.
“Entanglements are not intertwinings of pre-existing entities.
They are ontological inseparabilities — constitutive relations.”
In other words, you and the world co-arise — just as entangled particles do.
🔹 Philosophical Implications
Classical View |
Quantum Entanglement |
Objects have fixed, independent properties. |
Properties arise only through relation and measurement. |
Space separates things. |
Entangled systems transcend spatial separation. |
The observer is detached from the observed. |
The observer is part of the phenomenon. |
Cause and effect are local. |
Correlations are nonlocal and holistic. |
🔹 Summary (One-Liner)
Quantum entanglement shows us that the universe is not a collection of separate things, but a web of deep, irreducible relationships — where what something is depends on what it is entangled with.
Would you like a poetic expression of entanglement next? Or perhaps a comparison between quantum entanglement and Buddhist notions of interdependence (緣起)?