CN104601248A - Multi-party combined remote quantum state preparation method based on single atom operations - Google Patents

Abstract

The invention provides a multi-party combined remote quantum state preparation method based on single atom operations. Two senders are enabled to remotely assist a receiver to recover a secret single atom quantum bit state as shown in the description, wherein the first formula and the first formula both as shown in the description represent the ground state and the excited state of a two-energy level atom, and the parameters alpha and beta are real numbers and satisfy that alpha2+beta2=1; besides, all the information of the secret quantum bit is described by the parameters alpha and beta; all the information of the secret quantum bit is divided into two parts which are owned by the two senders, respectively. The information owned by the first sender is {alpha1, beta1}, while the information owned by the second sender is {alpha2, beta2}; a W type quantum entangled state, as shown in the description, composed of three two-energy level atoms is shared by the two senders and the receiver, wherein the first atom belongs to the first sender, while the second atom belongs to the first sender and the third atom belongs to the receiver.

Description

In many ways the long-range method preparing quantum state is combined based on monatomic operation

Technical field

The present invention relates to quantum information and communication network field, more particularly, the present invention relates to and a kind ofly in many ways combine the long-range method preparing quantum state based on monatomic operation.

Background technology

Quantum communications are a kind of Novel Communication modes of rising in recent years.By by information coding in the physical system with Quantum Properties, utilize the Quantum Properties of system mode, such as quantum entanglement, measure collapse, quantum state can not clone, comparatively classical communication is more safe to make quantum communications process, efficiently, anti-interference.Along with going deep into of studying quantum communication network, people propose various quantum communications method successively to solve the communication issue such as distribution, privacy share of the transmission of information, the encryption of information, secret key.

Suppose after some information process, such as, after a quantum secret sharing, the classical information describing a secret quantum bit content is split and is distributed in the different nodes of quantum network.That is, each node has only grasped a part of information of secret quantum bit state; Whole information of this secret quantum bit is had without any a node, can the information of Restore Secret quantum bit independently.Present problem is how can at a new node rebuild secret information.For this reason, propose in prior art and in many ways combine the long-range method preparing quantum state.These methods make use of the transmission channel of different Quantum Entangled States as quantum information respectively, complete the long-range preparation task of the associating of dissimilar quantum bit state.

But these research work only propose the method for quantum bit state being combined in many ways to long-range preparation from the aspect of mathematics, and for concrete physical system, the scheme in practice with operability is not proposed.And the experimental program that the researcher of minority puts forward is all the carrier using single photon as information, and single photon is often easy to be subject to the impact of environment and buries in oblivion in the operation of reality.

At present for the long-range technique study preparing quantum state of associating, nearly all do not discuss for concrete physical system, do not have to consider how to realize this process in the physical world of reality, the problem whether it has enforceability is not inquired into yet.Very few physical schemes, mainly inquires at photonic system.Although photon transmission speed is fast, the eliminating coherence time is short, easily buries in oblivion in the physical environment of reality.Further, long-range preparation in the process of quantum state does not need the carrier of information to transmit, but will carry out suitable operation to the carrier of information.As can be seen here, photonic system has been not the long-range desirable physical system preparing quantum state of associating.

Summary of the invention

Technical problem to be solved by this invention is for there is above-mentioned defect in prior art, from the operability of reality, propose one using Two level atom as the carrier of information, utilize the interaction between single Two level atom and Classical Electromagnetic Field, by the transmission channel of three atom W type Entangled States as quantum information, complete that two senders and recipient participate in, to the method for the long-range preparation of secret list quantum bit state.

In order to realize above-mentioned technical purpose, according to the present invention, providing and a kind ofly in many ways combining the long-range method preparing quantum state based on monatomic operation, wherein making the monatomic quantum bit state of two sender's remote assistances recipient's Restore Secret:

|φ>＝α|g>+β|e>；

Wherein | g>, | e> represents ground state and the excitation state of Two level atom respectively, parameter alpha, and β is real number, and the α that satisfies condition ²+ β ²=1; And parameter alpha, β describes all information of secret quantum bit, and all information of secret quantum bit are split as two parts, respectively have by two senders.

Preferably, the information that the first sender has is { α ₁, β ₁, the information that the second sender has is { α ₂, β ₂; A W type Quantum Entangled States be made up of three Two level atom is shared between two senders and a recipient

$|\mathrm{\ψ}>\frac{1}{3}{\left(\right|\mathrm{gge}>+|\mathrm{geg}>+|\mathrm{egg}>)}_{\mathrm{1,2,3}},$

Wherein the first atom belongs to the first sender, and the second atom belongs to the second sender, and the 3rd atom belongs to recipient.

Preferably, two senders respectively and establish quantum communications channel and classical communication channel between recipient.

Preferably, do not write to each other between two senders.

Preferably, described method comprises the steps:

First step: two senders allow the atom oneself had through a Classical Electromagnetic Field respectively, the frequency of Classical Electromagnetic Field should and jump frequency between atomic ground state and excitation state resonate; Two senders according to respective had about parameter alpha, the information { α of β _i, β _i, regulate the complex amplitude of Classical Electromagnetic Field coupling coefficient Ω between atom and Classical Fields _i, and the flight time t of atom in Classical Fields _i, thus meet the following conditions:

Wherein

Second step: after completing first step, the quantum state of the system that three atoms form will develop to following form:

Now, two senders measure the atom basic vector that it has respectively, judge that atom is in ground state | g> or excitation state | and e>, and measurement result is sent to recipient by classical channel;

Third step: recipient, according to from the measurement result of two senders and the fractionation mode of incorporating parametric α, β, judges the state residing for the 3rd atom, thus determine secret single quantum bit state | whether φ > is resumed.

Preferably, in third step, if to parameter alpha, the fractionation of β meets following relation,

${\mathrm{\α}}_2=\frac{\mathrm{\β}}{{\mathrm{\α}}_1},{\mathrm{\β}}_2=\frac{-{\mathrm{\α\α}}_1-{\mathrm{\β\β}}_1}{{\mathrm{\α}}_1^2}$

Then when the classical information from two senders shows the first atom and the second atom is all in ground state, namely the state of two atoms is | g> ₁| g> ₂, judge that the 3rd atom is in secret single quantum bit state.Preferably, in third step, if to parameter alpha, the fractionation of β meets following relation,

${\mathrm{\α}}_2=\frac{{\mathrm{\α\α}}_1+{\mathrm{\β\β}}_1}{{\mathrm{\α}}_1^2},{\mathrm{\β}}_2=\frac{\mathrm{\β}}{{\mathrm{\α}}_1}$

Then be in ground state when the classical information from two senders shows the first atom, and when the second atom is in excitation state, namely the state of two atoms is | g> ₁| e> ₂, judge that the 3rd atom is in secret single quantum bit state.

Preferably, in third step, if to parameter alpha, the fractionation of β meets following relation,

${\mathrm{\α}}_2=\frac{\mathrm{\β}}{{\mathrm{\α}}_1},{\mathrm{\β}}_2=\frac{-{\mathrm{\α\α}}_1-{\mathrm{\β\β}}_1}{{\mathrm{\α}}_1{\mathrm{\β}}_1}$

Then be in excitation state when the classical information from two senders shows the first atom, and when the second atom is in ground state, namely the state of two atoms is | e> ₁| g> ₂, judge that the 3rd atom is in secret single quantum bit state.

Preferably, in third step, if to parameter alpha, the fractionation of β meets following relation,

${\mathrm{\α}}_2=\frac{{\mathrm{\α\α}}_1+{\mathrm{\β\β}}_1}{{\mathrm{\α}}_1{\mathrm{\β}}_1},{\mathrm{\β}}_2=\frac{\mathrm{\β}}{{\mathrm{\α}}_1}$

Then when the classical information from two senders shows the first atom and the second atom is all in excitation state, namely the state of two atoms is | e> ₁| e> ₂, judge that the 3rd atom is in secret single quantum bit state.

The present invention proposes one take Two level atom as information carrier, can after quantum secret sharing the method for Restore Secret information again.In the method, each sender only grasps the secret information of a part, and secret information is throughput subchannel transmission, thus has good fail safe; Mainly, experimentally comparatively ripe at present utilize Classical Electromagnetic Field and single Two level atom interact the technology that the method relates to, and realize the technology manipulated state of atom, have actual operability; Meanwhile, have employed three atom W type Entangled States as quantum channel, better can overcome the impact of ambient noise, there is stronger anti-interference.

Accompanying drawing explanation

By reference to the accompanying drawings, and by reference to detailed description below, will more easily there is more complete understanding to the present invention and more easily understand its adjoint advantage and feature, wherein:

Fig. 1 schematically shows and in many ways combines the long-range flow chart preparing the method for quantum state according to the preferred embodiment of the invention based on monatomic operation.

It should be noted that, accompanying drawing is for illustration of the present invention, and unrestricted the present invention.Note, represent that the accompanying drawing of structure may not be draw in proportion.Further, in accompanying drawing, identical or similar element indicates identical or similar label.

Embodiment

In order to make content of the present invention clearly with understandable, below in conjunction with specific embodiments and the drawings, content of the present invention is described in detail.

In many ways the long-range method preparing quantum state is combined based on the interaction between single Two level atom and Classical Electromagnetic Field according to the preferred embodiment of the invention based on monatomic operation.Wherein, the sender that (1) is in different node by multidigit only knows the partial information of secret quantum state, instead of full detail, and thus, any sender can not betray the pot to the roses information; (2) only under multidigit sender coacts, can re-establish secret quantum state third party, either party absence all can cause the failure of preparation process, has ensured the fail safe of secret quantum state further; (3) passage of quantum-information transmission is that W type between three atoms tangles, and makes this method better can resist ambient noise; (4) two senders share the information to secret quantum state, and the mode that information is distributed is between the two related to success or not prepared by secret quantum state; (5) status representative of atom information.Utilize the interaction between Two level atom and Classical Electromagnetic Field, the manipulation to state of atom can be realized, that is complete the process to information.

The present invention relates to separated three participants (two senders and a recipient), make the monatomic quantum bit state of two sender's remote assistances recipient's Restore Secret:

|φ>＝α|g>+β|e>

Wherein represent ground state and the excitation state of Two level atom respectively, parameter alpha, β is real number, and the α that satisfies condition ²+ β ²=1.Parameter describe all information of secret quantum bit, they are split as two parts, respectively have by two senders.Might as well suppose, the information that the first sender Alice has is { α ₁, β ₁, the information that the second sender Bob has is { α ₂, β ₂.A W type Quantum Entangled States be made up of three Two level atom is shared between two senders and a recipient

$|\mathrm{\ψ}>\frac{1}{3}{\left(\right|\mathrm{gge}>+|\mathrm{geg}>+|\mathrm{egg}>)}_{\mathrm{1,2,3}},$

Wherein the first atom 1 belongs to the first sender Alice, and the second atom 2 belongs to the second sender Bob, and the 3rd atom 3 belongs to recipient Carol.Two senders respectively and establish quantum communications channel and classical communication channel between recipient; And in order to ensure the safety of secret quantum bit, do not write to each other between two senders.

In order to Restore Secret list quantum bit state, the concrete steps of three participants as shown in Figure 1, which schematically illustrates and in many ways combine the long-range flow chart preparing the method for quantum state according to the preferred embodiment of the invention based on monatomic operation.

As shown in Figure 1, comprise based on the long-range method preparing quantum state of in many ways combining of monatomic operation according to the preferred embodiment of the invention:

First step S1: two senders allow the atom that oneself has through a Classical Electromagnetic Field respectively, the frequency of Classical Electromagnetic Field should and jump frequency between atomic ground state and excitation state resonate.Two senders according to respective had about parameter alpha, the information { α of β _i, β _i, regulate the complex amplitude of Classical Electromagnetic Field coupling coefficient Ω between atom and Classical Fields _i, and the flight time t of atom in Classical Fields _i, thus meet the following conditions:

Wherein

Second step S2: after completing first step S1, the quantum state of the system that three atoms form will develop to following form:

Now, two senders measure the atom basic vector that it has respectively, judge that atom is in ground state | g> or excitation state | and e>, and measurement result is sent to recipient by classical channel.

There are four kinds of different possible situations in the measurement result of third step S3: two senders, corresponding to each measurement result, the 3rd atom 3 will be collapsed in different quantum states.Recipient Carol, according to from the classical information (measurement result) of two senders and incorporating parametric α, the fractionation mode of β, the state residing for the 3rd atom 3 that she grasps can be judged, thus know secret single quantum bit state | whether φ > has been resumed.

if to parameter alpha, the fractionation of β meets following relation,

${\mathrm{\α}}_2=\frac{\mathrm{\β}}{{\mathrm{\α}}_1},{\mathrm{\β}}_2=\frac{-{\mathrm{\α\α}}_1-{\mathrm{\β\β}}_1}{{\mathrm{\α}}_1^2}$

Then when the classical information from two senders shows the first atom 1 and the second atom 2 is all in ground state, namely the state of two atoms is | g> ₁| g> ₂, Carol can judge that the 3rd atom 3 is in secret single quantum bit state.

if to parameter alpha, the fractionation of β meets following relation,

${\mathrm{\α}}_2=\frac{{\mathrm{\α\α}}_1+{\mathrm{\β\β}}_1}{{\mathrm{\α}}_1^2},{\mathrm{\β}}_2=\frac{\mathrm{\β}}{{\mathrm{\α}}_1}$

Then be in ground state when the classical information from two senders shows the first atom 1, and when the second atom 2 is in excitation state, namely the state of two atoms is | g> ₁| e> ₂, Carol can judge that the 3rd atom 3 is in secret single quantum bit state.

if to parameter alpha, the fractionation of β meets following relation,

${\mathrm{\α}}_2=\frac{\mathrm{\β}}{{\mathrm{\α}}_1},{\mathrm{\β}}_2=\frac{-{\mathrm{\α\α}}_1-{\mathrm{\β\β}}_1}{{\mathrm{\α}}_1{\mathrm{\β}}_1}$

Then be in excitation state when the classical information from two senders shows the first atom 1, and when the second atom 2 is in ground state, namely the state of two atoms is | e> ₁| g> ₂, Carol can judge that the 3rd atom 3 is in secret single quantum bit state.

if to parameter alpha, the fractionation of β meets following relation,

${\mathrm{\α}}_2=\frac{{\mathrm{\α\α}}_1+{\mathrm{\β\β}}_1}{{\mathrm{\α}}_1{\mathrm{\β}}_1},{\mathrm{\β}}_2=\frac{\mathrm{\β}}{{\mathrm{\α}}_1}$

Then when the classical information from two senders shows the first atom 1 and the second atom 2 is all in excitation state, namely the state of two atoms is | e> ₁| e> ₂, Carol can judge that the 3rd atom 3 is in secret single quantum bit state.

If to parameter alpha, the fractionation of β does not meet above arbitrary a kind of relation, then regardless of the measurement result to the first atom 1 and the second atom 2, all can not complete the recovery to secret list quantum bit.

The present invention at least has following advantages:

(1) how a lot of correlative study achievement only realizes being coacted long-range reconstruction quantum state by multidigit sender from the discussion of mathematics aspect in the past.In contrast to this, we, in Two level atom and the so concrete physical system of classical light field, devise the method for the monatomic state of the long-range preparation of the associating jointly participated in by tripartite.And the interaction of atom and Classical Fields, be very ripe technology at present in laboratory, therefore, this method has good operability;

(2) relative to photonic system, the quantum state of atomic system has the longer eliminating coherence time, more stable in other words, is thus usually considered to desirable fixed bit.This makes it be more suitable for combining long-range preparation process than photon.Because prepare in the process of quantum state long-range, the physical system as information carrier does not need to be transferred to other positions, and only need to operate on it in this locality.Therefore we have employed the carrier of Two level atom as information;

(3) show the research of three-body entanglement at present, tangle the mode only having two kinds of non-equivalences between three quantized systems, one is GHZ type, and another kind is W type.Comparatively speaking, W type tangles and shows higher robustness and stronger Nonclassical Properties, thus make it be considered to quantum information process middle ideal tangle resource.This method adopts three former molecular W type Entangled States as the channel of quantum-information transmission, improves the antijamming capability of communication process.

In addition, it should be noted that, unless stated otherwise or point out, otherwise the term " first " in specification, " second ", " the 3rd " etc. describe only for distinguishing each assembly, element, step etc. in specification, instead of for representing logical relation between each assembly, element, step or ordinal relation etc.

Be understandable that, although the present invention with preferred embodiment disclose as above, but above-described embodiment and be not used to limit the present invention.For any those of ordinary skill in the art, do not departing under technical solution of the present invention ambit, the technology contents of above-mentioned announcement all can be utilized to make many possible variations and modification to technical solution of the present invention, or be revised as the Equivalent embodiments of equivalent variations.Therefore, every content not departing from technical solution of the present invention, according to technical spirit of the present invention to any simple modification made for any of the above embodiments, equivalent variations and modification, all still belongs in the scope of technical solution of the present invention protection.

Claims (9)

1. in many ways combine the long-range method preparing quantum state based on monatomic operation, wherein make the monatomic quantum bit state of two sender's remote assistances recipient's Restore Secret:

|φ＞＝α|g＞+β|e＞；

Wherein | g > 1|e > represents ground state and the excitation state of Two level atom respectively, parameter alpha, and β is real number, and the α that satisfies condition ²+ β ²=1; And parameter alpha, β describes all information of secret quantum bit, and all information of secret quantum bit are split as two parts, respectively have by two senders.

2. according to claim 1ly in many ways combine the long-range method preparing quantum state based on monatomic operation, it is characterized in that, the information that the first sender has is { α ₁, β ₁, the information that the second sender has is { α ₂, β ₂; A W type Quantum Entangled States be made up of three Two level atom is shared between two senders and a recipient

$|\mathrm{\Ψ}>=\frac{1}{\sqrt{3}}{\left(\right|\mathrm{gge}>+|\mathrm{geg}>+|\mathrm{egg}>)}_{\mathrm{1,2,3}},$

Wherein the first atom belongs to the first sender, and the second atom belongs to the second sender, and the 3rd atom belongs to recipient.

3. according to claim 1 and 2ly in many ways combine the long-range method preparing quantum state based on monatomic operation, it is characterized in that, two senders respectively and establish quantum communications channel and classical communication channel between recipient.

4. according to claim 1 and 2ly in many ways combine the long-range method preparing quantum state based on monatomic operation, it is characterized in that, do not write to each other between two senders.

5. according to claim 1 and 2ly in many ways combine the long-range method preparing quantum state based on monatomic operation, it is characterized in that described method comprises the steps:

First step: two senders allow the atom oneself had through a Classical Electromagnetic Field respectively, and the frequency of Classical Electromagnetic Field and the jump frequency between atomic ground state and excitation state resonate; Two senders according to respective had about parameter alpha, the information { α of β _i, β _i, regulate the complex amplitude of Classical Electromagnetic Field coupling coefficient Ω between atom and Classical Fields _i, and the flight time t of atom in Classical Fields _i, thus meet the following conditions:

Wherein θ _i=Ω _i| A _i| t _i;

Second step: after completing first step, the quantum state of the system that three atoms form will develop to following form:

$\begin{array}{c}|\mathrm{\Ψ}>=\frac{1}{\sqrt{3({\mathrm{\α}}_1^2+{\mathrm{\β}}_1^2)({\mathrm{\α}}_2^2+{\mathrm{\β}}_2^2)}}\{\left|\mathrm{gg}{>}_{\mathrm{1,2}}\right[(-{\mathrm{\α}}_1{\mathrm{\β}}_2-{\mathrm{\β}}_1{\mathrm{\α}}_2)|g{>}_3+{\mathrm{\α}}_1{\mathrm{\α}}_2|e{>}_3]\\ +\left|\mathrm{ge}{>}_{\mathrm{1,2}}\right[({\mathrm{\α}}_1{\mathrm{\α}}_2-{\mathrm{\β}}_1{\mathrm{\β}}_2)|g{>}_3+{\mathrm{\α}}_1{\mathrm{\β}}_2|e{>}_3]+|\mathrm{eg}{>}_{\mathrm{1,2}}[(-{\mathrm{\β}}_1{\mathrm{\β}}_2\\ -{\mathrm{\β}}_1{\mathrm{\α}}_2)|g{>}_3+{\mathrm{\α}}_1{\mathrm{\α}}_2|e{>}_3]+|\mathrm{ee}{>}_{\mathrm{1,2}}\left[({\mathrm{\β}}_1{\mathrm{\α}}_2-{\mathrm{\β}}_1{\mathrm{\β}}_2)\right|g{>}_3\\ +{\mathrm{\α}}_1{\mathrm{\β}}_2\left|e{>}_3\right].\end{array}---\left(1\right)$

Now, two senders measure the atom basic vector that it has respectively, judge that atom is in ground state | g > or excitation state | and e >, and measurement result is sent to recipient by classical channel;

Third step: recipient, according to from the measurement result of two senders and the fractionation mode of incorporating parametric α, β, judges the state residing for the 3rd atom, thus determine secret single quantum bit state | whether φ > is resumed.

6. according to claim 1 and 2ly in many ways combine the long-range method preparing quantum state based on monatomic operation, it is characterized in that, in third step, if to parameter alpha, the fractionation of β meets following relation,

${\mathrm{\α}}_2=\frac{\mathrm{\β}}{{\mathrm{\α}}_1},{\mathrm{\β}}_2=\frac{{-\mathrm{\α\α}}_1-{\mathrm{\β\β}}_1}{{\mathrm{\α}}_1^2}$

Then when the classical information from two senders shows the first atom and the second atom is all in ground state, namely the state of two atoms is | g > ₁| g > ₂, judge that the 3rd atom is in secret single quantum bit state.

7. according to claim 1 and 2ly in many ways combine the long-range method preparing quantum state based on monatomic operation, it is characterized in that, in third step, if to parameter alpha, the fractionation of β meets following relation,

${\mathrm{\α}}_2=\frac{{\mathrm{\α\α}}_1+{\mathrm{\β\β}}_1}{{\mathrm{\α}}_1^2},{\mathrm{\β}}_2=\frac{\mathrm{\β}}{{\mathrm{\α}}_1}$

Then be in ground state when the classical information from two senders shows the first atom, and when the second atom is in excitation state, namely the state of two atoms is | g > ₁| e > ₂, judge that the 3rd atom is in secret single quantum bit state.

8. according to claim 1 and 2ly in many ways combine the long-range method preparing quantum state based on monatomic operation, it is characterized in that, in third step, if to parameter alpha, the fractionation of β meets following relation,

${\mathrm{\α}}_2=\frac{\mathrm{\β}}{{\mathrm{\α}}_1},{\mathrm{\β}}_2=\frac{-{\mathrm{\α\α}}_1-{\mathrm{\β\β}}_1}{{\mathrm{\α}}_1{\mathrm{\β}}_1}$

Then be in excitation state when the classical information from two senders shows the first atom, and when the second atom is in ground state, namely the state of two atoms is | e > ₁| g > ₂, judge that the 3rd atom is in secret single quantum bit state.

9. according to claim 1 and 2ly in many ways combine the long-range method preparing quantum state based on monatomic operation, it is characterized in that, in third step, if to parameter alpha, the fractionation of β meets following relation,

${\mathrm{\α}}_2=\frac{{\mathrm{\α\α}}_1+{\mathrm{\β\β}}_1}{{\mathrm{\α}}_1{\mathrm{\β}}_1},{\mathrm{\β}}_2=\frac{\mathrm{\β}}{{\mathrm{\α}}_1}$

Then when the classical information from two senders shows the first atom and the second atom is all in excitation state, namely the state of two atoms is | e > ₁| e > ₂, judge that the 3rd atom is in secret single quantum bit state.