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Deterministic Creation of Macroscopic Cat States.

Lombardo D, Twamley J - Sci Rep (2015)

Bottom Line: Despite current technological advances, observing quantum mechanical effects outside of the nanoscopic realm is extremely challenging.In this work we develop a completely deterministic method of macroscopic quantum state creation.It is found that by using a Bose-Einstein condensate as a membrane high fidelity cat states with spatial separations of up to ∼300 nm can be achieved.

View Article: PubMed Central - PubMed

Affiliation: Centre for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109, Australia.

ABSTRACT
Despite current technological advances, observing quantum mechanical effects outside of the nanoscopic realm is extremely challenging. For this reason, the observation of such effects on larger scale systems is currently one of the most attractive goals in quantum science. Many experimental protocols have been proposed for both the creation and observation of quantum states on macroscopic scales, in particular, in the field of optomechanics. The majority of these proposals, however, rely on performing measurements, making them probabilistic. In this work we develop a completely deterministic method of macroscopic quantum state creation. We study the prototypical optomechanical Membrane In The Middle model and show that by controlling the membrane's opacity, and through careful choice of the optical cavity initial state, we can deterministically create and grow the spatial extent of the membrane's position into a large cat state. It is found that by using a Bose-Einstein condensate as a membrane high fidelity cat states with spatial separations of up to ∼300 nm can be achieved.

No MeSH data available.


Related in: MedlinePlus

Suggested schematic experimental configuration for effective flipping of the MITM optical cavity fields and the disentanglement operation.The three cavities necessary for both the preparation and disentanglement of the cat state are colour coded. The original MITM setup where the membrane separates two Fabry-Pérot cavities is colour coded via blue and red optical paths with vertically polarized photons (shown by vertical double arrows). The Electro Optic Quater Wave Plates [EOP] (A, B) are used to rapidly switch the polarisation of the light fields to horizontal polarization. Due to the presence of polarization dependent beam displacers, horizontally polarized light propagates in a ring resonator (green optical path), and this evolution is left on for the brief duration required to flip the optical fields on either side of the membrane. Then the EOPs (A, B) are switched back to return to the original Fabry-Pérot MITM setup. When finally one wishes to disentangle the membrane and optical fields EOPs (C, D) are used to route the photons into another ring resonator that also includes an atomic ensemble.
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f5: Suggested schematic experimental configuration for effective flipping of the MITM optical cavity fields and the disentanglement operation.The three cavities necessary for both the preparation and disentanglement of the cat state are colour coded. The original MITM setup where the membrane separates two Fabry-Pérot cavities is colour coded via blue and red optical paths with vertically polarized photons (shown by vertical double arrows). The Electro Optic Quater Wave Plates [EOP] (A, B) are used to rapidly switch the polarisation of the light fields to horizontal polarization. Due to the presence of polarization dependent beam displacers, horizontally polarized light propagates in a ring resonator (green optical path), and this evolution is left on for the brief duration required to flip the optical fields on either side of the membrane. Then the EOPs (A, B) are switched back to return to the original Fabry-Pérot MITM setup. When finally one wishes to disentangle the membrane and optical fields EOPs (C, D) are used to route the photons into another ring resonator that also includes an atomic ensemble.

Mentions: Both of the above tasks are implemented via polarization control of the optical paths taken by the photons which we now describe in more detail. The schematic experiment achieves the first task, interchanging the optical consists of a multi-cavity system where each cavity is distinguished by the polarisation of the light in the system, shown in Fig. 5. Each of the cavities are separated through the use of appropriately positioned beam displacers and alternated between by the activation of Electro-optic quarter wave plates (EOP). For vertically polarised light, the cavity resembles that of a Fabry-Pérot cavity where the membrane is positioned in the center. The Fabry-Pérot cavity is shown in Fig. 5 by red and blue lines, each corresponding to the left/right cavities. This means that if the light in the system is vertically polarised and the natural transmission rate of the membrane satisfies the system can be approximately described by Eq. (6). If the light is horizontally polarised the system corresponds to a Ring cavity containing the membrane, shown as green in Fig. 5. In this case the effective transmission rate of the membrane drastically increases as the light can freely travel between the left/right cavities and hence the system can be approximately described by the highly transmissive Hamiltonian, Eq. (8). The evolution described by Eq. (11), which is required to drive the displacement of the membrane, could be realised by alternating between these two cavities through the activation of the EOPs A and B in Fig. 5. Introduction of many atoms into the system could be achieved by introducing a third cavity using a similar technique as above. At the end of the evolution, Eq. (11), the system remains in the highly reflective regime. If at this time the EOPs C and D in Fig. 5 are activated the system will again resemble a Ring cavity, but one which contains M atoms as well as the membrane. Provided that the atoms are each prepared in the optical ground state, Δms = ±1 transitions will be excited as the light of each mode is left/right hand polarised by two separate quarter wave plates, entangling the membrane with the atomic states.


Deterministic Creation of Macroscopic Cat States.

Lombardo D, Twamley J - Sci Rep (2015)

Suggested schematic experimental configuration for effective flipping of the MITM optical cavity fields and the disentanglement operation.The three cavities necessary for both the preparation and disentanglement of the cat state are colour coded. The original MITM setup where the membrane separates two Fabry-Pérot cavities is colour coded via blue and red optical paths with vertically polarized photons (shown by vertical double arrows). The Electro Optic Quater Wave Plates [EOP] (A, B) are used to rapidly switch the polarisation of the light fields to horizontal polarization. Due to the presence of polarization dependent beam displacers, horizontally polarized light propagates in a ring resonator (green optical path), and this evolution is left on for the brief duration required to flip the optical fields on either side of the membrane. Then the EOPs (A, B) are switched back to return to the original Fabry-Pérot MITM setup. When finally one wishes to disentangle the membrane and optical fields EOPs (C, D) are used to route the photons into another ring resonator that also includes an atomic ensemble.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561959&req=5

f5: Suggested schematic experimental configuration for effective flipping of the MITM optical cavity fields and the disentanglement operation.The three cavities necessary for both the preparation and disentanglement of the cat state are colour coded. The original MITM setup where the membrane separates two Fabry-Pérot cavities is colour coded via blue and red optical paths with vertically polarized photons (shown by vertical double arrows). The Electro Optic Quater Wave Plates [EOP] (A, B) are used to rapidly switch the polarisation of the light fields to horizontal polarization. Due to the presence of polarization dependent beam displacers, horizontally polarized light propagates in a ring resonator (green optical path), and this evolution is left on for the brief duration required to flip the optical fields on either side of the membrane. Then the EOPs (A, B) are switched back to return to the original Fabry-Pérot MITM setup. When finally one wishes to disentangle the membrane and optical fields EOPs (C, D) are used to route the photons into another ring resonator that also includes an atomic ensemble.
Mentions: Both of the above tasks are implemented via polarization control of the optical paths taken by the photons which we now describe in more detail. The schematic experiment achieves the first task, interchanging the optical consists of a multi-cavity system where each cavity is distinguished by the polarisation of the light in the system, shown in Fig. 5. Each of the cavities are separated through the use of appropriately positioned beam displacers and alternated between by the activation of Electro-optic quarter wave plates (EOP). For vertically polarised light, the cavity resembles that of a Fabry-Pérot cavity where the membrane is positioned in the center. The Fabry-Pérot cavity is shown in Fig. 5 by red and blue lines, each corresponding to the left/right cavities. This means that if the light in the system is vertically polarised and the natural transmission rate of the membrane satisfies the system can be approximately described by Eq. (6). If the light is horizontally polarised the system corresponds to a Ring cavity containing the membrane, shown as green in Fig. 5. In this case the effective transmission rate of the membrane drastically increases as the light can freely travel between the left/right cavities and hence the system can be approximately described by the highly transmissive Hamiltonian, Eq. (8). The evolution described by Eq. (11), which is required to drive the displacement of the membrane, could be realised by alternating between these two cavities through the activation of the EOPs A and B in Fig. 5. Introduction of many atoms into the system could be achieved by introducing a third cavity using a similar technique as above. At the end of the evolution, Eq. (11), the system remains in the highly reflective regime. If at this time the EOPs C and D in Fig. 5 are activated the system will again resemble a Ring cavity, but one which contains M atoms as well as the membrane. Provided that the atoms are each prepared in the optical ground state, Δms = ±1 transitions will be excited as the light of each mode is left/right hand polarised by two separate quarter wave plates, entangling the membrane with the atomic states.

Bottom Line: Despite current technological advances, observing quantum mechanical effects outside of the nanoscopic realm is extremely challenging.In this work we develop a completely deterministic method of macroscopic quantum state creation.It is found that by using a Bose-Einstein condensate as a membrane high fidelity cat states with spatial separations of up to ∼300 nm can be achieved.

View Article: PubMed Central - PubMed

Affiliation: Centre for Engineered Quantum Systems, Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109, Australia.

ABSTRACT
Despite current technological advances, observing quantum mechanical effects outside of the nanoscopic realm is extremely challenging. For this reason, the observation of such effects on larger scale systems is currently one of the most attractive goals in quantum science. Many experimental protocols have been proposed for both the creation and observation of quantum states on macroscopic scales, in particular, in the field of optomechanics. The majority of these proposals, however, rely on performing measurements, making them probabilistic. In this work we develop a completely deterministic method of macroscopic quantum state creation. We study the prototypical optomechanical Membrane In The Middle model and show that by controlling the membrane's opacity, and through careful choice of the optical cavity initial state, we can deterministically create and grow the spatial extent of the membrane's position into a large cat state. It is found that by using a Bose-Einstein condensate as a membrane high fidelity cat states with spatial separations of up to ∼300 nm can be achieved.

No MeSH data available.


Related in: MedlinePlus