HOW can entanglement be observed experimentally?

In summary: The general notion is that M String theory if proven is theory of everything. But without explaining entanglement how does it become TOE.The general notion is that M String theory if proven is theory of everything. But without explaining entanglement, how does it become a theory of everything? In summary, without explaining entanglement, M String theory would not be a theory of everything.
  • #1
dpa
147
0
hi all

i have two questions.
1. Quantum entanglement is observed experimentally. But how can that be. Does not Quantum decoherence effect it from being observed?

2.The general notion is that M String theory if proven is theory of everything. But without explaining entanglement how does it become TOE.
 
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  • #2
dpa said:
hi all

i have two questions.
1. Quantum entanglement is observed experimentally. But how can that be. Does not Quantum decoherence effect it from being observed?

Entanglement is typically detected through the measurement of correlations between the entangled particles. They need to display the appropriate non-local correlations to be considered entangled. Decoherence can indeed destroy these features, but decoherence only sets in at a particular time scale, which is given by how strong the coupling to the surrounding environment is, how much the surroundings fluctuate, and also how big your object is. This gives a time scale on which decoherence effects sets in, but as long as you are able to read out all necessary data before that time, you are fine.
 
  • #3
Zarqon said:
Entanglement is typically detected through the measurement of correlations between the entangled particles. They need to display the appropriate non-local correlations to be considered entangled. Decoherence can indeed destroy these features, but decoherence only sets in at a particular time scale, which is given by how strong the coupling to the surrounding environment is, how much the surroundings fluctuate, and also how big your object is. This gives a time scale on which decoherence effects sets in, but as long as you are able to read out all necessary data before that time, you are fine.

I second Zarqon's explanation. I would also like to point out that while decoherence is a major problem in many experiments in quantum mechanics (such as those involving electrons or ion traps), its is not nearly such an issue in quantum optics. Entangled photon pairs have very few problems with decoherence, one of the reasons that they are attractive for quantum computing (although they possesses other disadvantages). As I recall, Zeilinger et. al. have done experiments where they separate two entangled photons and then send one several miles away where it is collected via telescope and the correlations between them survive. The specifics of what measurements are done to verify entanglement depends on the particular experiment, but it can certainly be done.
 

1. What is entanglement and why is it important to observe it experimentally?

Entanglement is a quantum phenomenon in which two or more particles become connected in such a way that the state of one particle is dependent on the state of the other particles, regardless of the distance between them. It is important to observe entanglement experimentally because it is a key concept in quantum mechanics and has potential applications in quantum computing and communication.

2. How can entanglement be created in a laboratory setting?

Entanglement can be created in a laboratory setting through various methods, including using a beam splitter and polarizing filters, using entangling gates in quantum circuits, or using quantum state preparation techniques. These methods allow for the manipulation of quantum systems to create entangled states.

3. What are some commonly used techniques for observing entanglement?

Some commonly used techniques for observing entanglement include quantum state tomography, Bell inequality measurements, and quantum correlation measurements. These techniques involve measuring the properties of entangled particles to demonstrate their interconnectedness.

4. How can entanglement be measured and quantified?

Entanglement can be measured and quantified through various methods, such as entanglement entropy, concurrence, and logarithmic negativity. These measures provide a way to quantify the degree of entanglement between particles and can be used to compare different entangled systems.

5. What challenges are faced in observing entanglement experimentally?

One of the main challenges in observing entanglement experimentally is the fragility of entangled states. These states can easily become disrupted by external factors, such as noise and decoherence. Additionally, the complexity of measuring and quantifying entanglement can also present challenges for experimental observation.

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