Quantum computer apparatus

• US 7,466,725 B2
• Filed: 08/29/2005
• Issued: 12/16/2008
• Est. Priority Date: 08/30/2004
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Ichimura, Kouichi, Shiokawa, Noritsugu, Goto, Hayato
• Primary Examiner(s): Nguyen; Dung T
• Application Number:
  US11/212,690
• Publication Number:
  US 20060043357A1
• Time in Patent Office: 1,205 Days
• Field of Search: 372/2, 372/23, 372/69
• US Class Current: 372/2
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G06N 10/00 Quantum computing, i.e. information processing based on quantum-mechanical phenomena

Abstract

Quantum computer includes optical resonator including system group containing systems each having energy states highest-energy state |3>, and other two energy states |1> and |2>, fourth or more states |p>, transition angular frequency (ω_ij) between |i> and |j>, homogeneous broadening (Δω_homo,ij) in transition angular frequency between |i> and |j>, optical resonator having resonator modes, ω_ck of k^th resonator mode, and emitting unit configured to emit light beam to system group, and wherein |ω_cl−ω_cm|>Δω_homo,23, system group includes system subgroups A_q having respective ω₂₃ which resonate with respective ω_cq of resonator modes, and emitting unit is arranged to apply light beam of two wavelengths and other light beam to s(1)^th quantum bit A_qs(1) (s(1)1˜r) formed of r systems selected from each A_q, light beam of two wavelengths simultaneously causing two-photon resonance on A_q at ω₁₂ or ω_1p, other light beam simultaneously causing one-photon resonance on A_q at ω₁₃ or ω_p3.

Claims

1. A quantum computer apparatus, comprising:

an optical resonator including a physical system group containing a plurality of physical systems each having at least three energy states;

a highest-energy state expressed by |3>

, and other two energy states expressed by |1> and

|2>

, and if exist, fourth or more states being expressed by |p>

, p being a natural number not less than 4, a transition angular frequency corresponding to a transition between |i> and

j>

being expressed by ω

_ij, a homogeneous broadening of a transition between |i> and

|j>

being expressed by Δ

ω

_homo,ij, and i and j being natural numbers, the optical resonator having a plurality of resonator modes, an angular frequency of a k^th resonator mode included in the resonator modes being expressed by ω

_ck, k being a natural number; and

an emitting unit configured to emit a light beam to the physical system group in the optical resonator,

and wherein;

a difference between angular frequencies of selected two resonator modes of the resonator modes satisfies |ω

_cl−

ω

_cm|>

Δ

ω

_homo,23, where l and m indicate an l^th resonator mode and an m^th resonator mode included in the resonator modes, respectively;

the physical system group includes a plurality of physical system subgroups A_q having respective transition angular frequencies ω

₂₃ which resonate with respective angular frequencies ω

_cq of the resonator modes of the optical resonator, q being a natural number; and

the emitting unit is arranged to apply the light beam of two wavelengths and other light beam to an s(1)^th quantum bit A_qs(1) included in quantum bits A_qs formed of r physical systems selected from each of the physical system subgroups A_q, r being a natural number, s being natural numbers ranging from l to r, the light beam of the two wavelengths simultaneously causing two-photon resonance on s(1)^th quantum bits of the physical system subgroups A_q at a transition angular frequency ω

₁₂ or ω

_lp, the other light beam simultaneously causing one-photon resonance on the s(1)^th quantum bits of the physical system subgroups A_q at a transition angular frequency ω

₁₃ or ω

_p3.

2. The apparatus according to claim 1, wherein the physical systems are formed of rare earth ions contained in an oxide crystal.

3. The apparatus according to claim 1, wherein the emitting unit includes a laser medium contained in an optical resonator having a same free spectral range as the optical resonator including the physical system group, and utilizes a light beam having a plurality of angular frequencies separated by a free spectral range of an angular frequency ω

FSR acquired by multi-mode oscillation.

4. The apparatus according to claim 3, further comprising:

a first acoustooptical effect element which performs frequency shift and control of intensity of the light beam having the angular frequencies separated by the free spectral range of the angular frequency ω

_FSR acquired by multi-mode oscillation, and operates one of quantum bits belonging to the physical system subgroups A_q;

a beam splitter which splits a light beam, having passed through the first acoustooptical effect element, into a plurality of light beams without changing a multi-mode state of the light beam;

a plurality of filters which pass the light beams to acquire light beams resonating with frequencies corresponding to the respective physical system subgroups A_q; and

a second acoustooptical effect element which adjusts frequencies of the light beams having passed through the filters to make the light beams for operating an S^th quantum bit belonging to each of the physical system subgroups A_q.

5. A quantum computer apparatus, comprising:

an optical resonator including a physical system group containing a plurality of physical systems each having at least three energy states;

a highest-energy state expressed by |3>

, and other two energy states expressed by |1> and

|2>

, and if exist, fourth or more states being expressed by |p>

, p being a natural number not less than 4, a transition angular frequency corresponding to a transition between |i> and

|j>

being expressed by ω

_ij, a homogeneous broadening of a transition between |i> and

|j>

being expressed by Δ

ω

_homo,ij, an inhomogeneous broadening of a transition between |i> and

|j>

being expressed by Δ

ω

_inhomo,ij, i and j being natural numbers, the physical system group having a plurality of resonator “

00”

modes separate from each other by a free spectral range of an angular frequency ω

_FSR, an angular frequency of a k^th resonator mode included in the resonator modes being expressed by ω

_00k, k being a natural number; and

an emitting unit configured to emit a light beam to the physical system group in the optical resonator,

and wherein;

the optical resonator including the physical system group satisfy Δ

ω

_homo,23<

ω

FSR and ω

_FSR<

Δ

ω

_inhomo,23, and the physical system group includes a plurality of physical system subgroups A_q having respective transition angular frequencies ω

₂₃ which resonate with respective angular frequencies ω

_00q of the resonator modes of the optical resonator, q being a natural number; and

the emitting unit is arranged to apply a light beam of two wavelengths and other light beam to an s(1)^th quantum bit A_qs(1) included in quantum bits A_qs formed of r physical systems selected from each of the physical system subgroups A_q, r being a natural number, s being natural numbers ranging from 1 to r, the light beam of the two wavelengths simultaneously causing two-photon resonance on s(1) quantum bits of the physical system subgroups A_q at a transition angular frequency ω

₁₂ or ω

_1p, the other light beam simultaneously causing one-photon resonance on the s(1)^th quantum bits of the physical system subgroups A_q at a transition angular frequency ω

₁₃ or ω

_p3.

6. The apparatus according to claim 5, wherein the physical systems are formed of rare earth ions contained in an oxide crystal.

7. The apparatus according to claim 5, wherein the emitting unit includes a laser medium contained in an optical resonator having a same free spectral range as the optical resonator including the physical system group, and utilizes a light beam having a plurality of angular frequencies separated by a free spectral range of an angular frequency (DFSR acquired by multi-mode oscillation.

8. The apparatus according to claim 7, further comprising:

a first acoustooptical effect element which performs frequency shift and control of intensity of the light beam having the angular frequencies separated by the free spectral range of the angular frequency ω

_FSR acquired by multi-mode oscillation, and operates one of quantum bits belonging to the physical system subgroups A_q;

a beam splitter which splits a light beam, having passed through the first acoustooptical effect element, into a plurality of light beams without changing a multi-mode state of the light beam;

a plurality of filters which pass the light beams to acquire light beams resonating with frequencies corresponding to the respective physical system subgroups A_q; and

a second acoustooptical effect element which adjusts frequencies of the light beams having passed through the filters to make the light beams for operating an s^th quantum bit belonging to each of the physical system subgroups A_q.

9. A quantum computer apparatus, comprising:

optical resonator means including a physical system group containing a plurality of physical systems each having at least three energy states;

a highest-energy state expressed by |3>

, and other two energy states expressed by |1> and

|2>

, and if exist, fourth or more states being expressed by |p>

, p being a natural number not less than 4, a transition angular frequency corresponding to a transition between |i> and

|j>

being expressed by ω

_ij, a homogeneous broadening of a transition between |i> and

|j>

being expressed by Δ

ω

_homo,ij, and i and j being natural numbers, the optical resonator means having a plurality of resonator modes, an angular frequency of a k^th resonator mode included in the resonator modes being expressed by ω

_ck, k being a natural number; and

light emitting means for emitting a light beam to the physical system group in the optical resonator means,

and wherein;

a difference between angular frequencies of selected two resonator modes of the resonator modes satisfies |ω

_cl−

ω

_cm|>

Δ

ω

_homo,23, where 1 and m indicate an 1^th resonator mode and an m^th resonator mode included in the resonator modes, respectively;

the physical system group includes a plurality of physical system subgroups A_q having respective transition angular frequencies ω

₂₃ which resonate with respective angular frequencies ω

_cq of the resonator modes of the optical resonator, q being a natural number; and

the light emitting means is arranged to apply the light beam of two wavelengths and other light beam to an s(1)^th quantum bit A_qs(1) included in quantum bits A_qs formed of r physical systems selected from each of the physical system subgroups A_q, r being a natural number, s being natural numbers ranging from 1 to r, the light beam of the two wavelengths simultaneously causing two-photon resonance on s(1)^th quantum bits of the physical system subgroups A_q at a transition angular frequency ω

₁₂ or ω

_1p, the other light beam simultaneously causing one-photon resonance on the s(1)^th quantum bits of the physical system subgroups A_q at a transition angular frequency ω

₁₃ or ω

_p3.

10. The apparatus according to claim 9, wherein the physical systems are formed of rare earth ions contained in an oxide crystal.

11. The apparatus according to claim 9, wherein the light emitting means includes a laser medium contained in an optical resonator having a same free spectral range as the optical resonator means including the physical system group, and utilizes a light beam having a plurality of angular frequencies separated by a free spectral range of an angular frequency ω

_FSR acquired by multi-mode oscillation.

12. The apparatus according to claim 11, further comprising:

first acoustooptical effect means for performing frequency shift and control of intensity of the light beam having the angular frequencies separated by the free spectral range of the angular frequency ω

_FSR acquired by multi-mode oscillation, and operates one of quantum bits belonging to the physical system subgroups A_q;

beam splitting means for splitting a light beam, having passed through the first acoustooptical effect means, into a plurality of light beams without changing a multi-mode state of the light beam;

a plurality of filters which pass the light beams to acquire light beams resonating with frequencies corresponding to the respective physical system subgroups A_q; and

second acoustooptical effect means which adjusts frequencies of the light beams having passed through the filters to make the light beams for operating an s quantum bit belonging to each of the physical system subgroups A_q.

13. A quantum computer apparatus, comprising:

optical resonator means including a physical system group containing a plurality of physical systems each having at least three energy states;

a highest-energy state expressed by |3>

, and other two energy states expressed by |1> and

|2>

, and if exist, fourth or more states being expressed by |p>

, p being a natural number not less than 4, a transition angular frequency corresponding to a transition between |i> and

|j>

being expressed by ω

_ij, a homogeneous broadening of a transition between |i> and

|j>

being expressed by Δ

ω

_homo,ij, an inhomogeneous broadening of a transition between |i> and

|j>

being expressed by Δ

ω

_inhomo,ij, i and j being natural numbers, the physical system group having a plurality of resonator “

00”

modes separate from each other by a free spectral range of an angular frequency ω

_FSR, an angular frequency of a k^th resonator mode included in the resonator modes being expressed by ω

_00k, k being a natural number; and

light emitting means for emitting a light beam to the physical system group in the optical resonator means,

and wherein;

the optical resonator means including the physical system group satisfy Δ

ω

_homo,23 >

ω

_FSR and ω

_FSR>

Δ

ω

_inhomo,23, and the physical system group includes a plurality of physical system subgroups A_q having respective transition angular frequencies ω

₂₃ which resonate with respective angular frequencies ω

_00q of the resonator modes of the optical resonator means, q being a natural number; and

the light emitting means is arranged to apply a light beam of two wavelengths and other light beam to an s(1) quantum bit A_qs(1)included in quantum bits A_qs formed of r physical systems selected from each of the physical system subgroups A_q, r being a natural number, s being natural numbers ranging from 1 to r, the light beam of the two wavelengths simultaneously causing two-photon resonance on s(1)^th quantum bits of the physical system subgroups A_q at a transition angular frequency ω

₁₂ or ω

_1p, the other light beam simultaneously causing one-photon resonance on the s(1)^th quantum bits of the physical system subgroups A_q at a transition angular frequency ω

₁₃ or ω

_p3.

14. The apparatus according to claim 13, wherein the physical systems are formed of rare earth ions contained in an oxide crystal.

15. The apparatus according to claim 13, wherein the light emitting means includes a laser medium contained in an optical resonator having a same free spectral range as the optical resonator means including the physical system group, and utilizes a light beam having a plurality of angular frequencies separated by a free spectral range of an angular frequency ω

_FSR acquired by multi-mode oscillation.

16. The apparatus according to claim 15, further comprising:

first acoustooptical effect means for performing frequency shift and control of intensity of the light beam having the angular frequencies separated by the free spectral range of the angular frequency WFSR acquired by multi-mode oscillation, and operates one of quantum bits belonging to the physical system subgroups A_q;

beam splitting means for splitting a light beam, having passed through the first acoustooptical effect means, into a plurality of light beams without changing a multi-mode state of the light beam;

a plurality of filters which pass the light beams to acquire light beams resonating with frequencies corresponding to the respective physical system subgroups A_q; and

second acoustooptical effect means which adjusts frequencies of the light beams having passed through the filters to make the light beams for operating an s^th quantum bit belonging to each of the physical system subgroups A_q.